THE 


S  T  U  D  E  N  T'S 


PRACTICAL  CHEMISTRY, 


A    TEXT-BOOK    ON 


CHEMICAL  PHYSICS  AND  INORGANIC  AND 
ORGANIC  CHEMISTRY. 


BY 

HENRY  MORTON,  A.M.,  AND  ALBERT  R.  LEEDS,  A.M., 

EMERITUS  PROFESSOR  OF  CHEMISTRY  IN  THE  PROFESSOR  OF  CHEMISTRY  AND  METALLURGY 

PHILADELPHIA  DENTAL  COLLEGE ;  ALSO  IN  THE  PHILADELPHIA  DENTAL  COLLEGE, 

PROFESSOR    OF    MECHANICS    AND  AND  PROFESSOR  OF  CHEMISTRY  IN 

RESIDENT  SECRETARY  OF  THE  THE  FRANKLIN  INSTITUTE 

FRANKLIN  INSTITUTE.  OF  PENNSYLVANIA. 


P  HILAD  E  L  PHIA 
J.    B.    LIPPINCOTT    & 

1866. 


o 


Entered  according  to  Act  of  Congress,  in  the  year  1865,  by 
J.  B.  LIPPINCOTT  &  CO. 

In  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the  Eastern 
District  of  Pennsylvania. 


PREFACE. 


THE  authors  of  the  following  pages  have  made 
it  their  object  to  produce  a  book  of  practical  use  to 
the  student,  by  furnishing  him  with  clear  and  simple 
explanations  of  the  subject ;  and  to  those  more  pro- 
ficient in  scientific  learning,  by  giving  them  in  small 
compass,  convenient  ^emoranda  of  important  facts, 
numbers,  references,  etc.  The  effort  has  also  been 
made  to  embody  all  the  valuable  novelties  in  the 
branches  discussed  (many  of  which  have  not  yet  been 
introduced  in  any  text -book),  and  thus  to  bring  this 
work  down  to  the  present  time. 

In  the  explanation  of  laws  and  theories,  mathemat- 
ical precision  of  statement  has  been  less  studied  than 
the  expression  of  a  clear  idea,  in  such  form  as  would 
be  readily  apprehended  by  one  not  previously  con- 
versant with  the  subject.  Thus,  such  explanations 
as  those  on  pages  30  and  62  may  be  well  passed  over 

(iii) 


IV  PREFACE. 

by  the  well-read  man  of  science,  as  partaking  more 
of  the  nature  of  similies  than  precise  statements ;  but 
they  will  have  done  the  work  intended  for  them,  if 
they  furnish  the  beginner  with  such  a  general  view 
of  the  subject  concerned,  as  will  aid  him  in  recollect- 
ing its  facts,  and  pave  the  way  for  a  more  precise 
and  abstract  idea,  in  the  future. 


CONTENTS. 

Part  I. 
CHEMICAL  PHYSICS. 

PAGE. 

GENERAL  PROPERTIES  OF  MATTER      ....  9-10 

MECHANICAL  FORCES         .....  10 

Gravitation — Specific  Gravity    .             .             .  10-12 

Cohesion — Adhesion — Capillary  Attraction — Diffusion  12-15 

Repulsion             .             .             .             .             .             .  15 

—Polarity          ......  16 

HEAT  ........  16-37 

Sources          .             .             .             .             .             .  17-18 

Measurement      ......  18-19 

Specific  Heat              .....  20-21 

Effects  of  Heat   .  .  .  .  .  .21-33 

Expansion              .....  21-23 

Fusion — Latent  Heat — Freezing  Mixtures     .             .  23-26 
Vaporization  —  Latent  Heat  —  Freezing  by  Evapo- 

'rSttoTP-Distillation        .             .             .             .  26-33 

Transfer  of  Heat            .....  33-37 

Conduction  — Spheroidal  State     .             .             .  33-35 

Convection       ......  35-36 

Radiation  ......  36-37 

LIGHT             .......  38-71 

Sources          ......  38 

Interference — Diffraction           ....  39-40 

Reflection      ......  41-45 

Refraction — Lenses — Double  Refraction           .             .  45-51 

Composition — Prisms            ....  61-58 

Spectrum  Analysis      .....  55-56 

Absorption  Bands              ....  56-58 

Fluorescence  and  Phosphorescence       .             .             .  58-59 

Dispersion     ......  60-62 

"^-Polarized  Light  ......  62-71 

(v) 


VI  CONTENTS. 

ELECTRICITY,  THEORY  OP  ....  71-89 

Statical  Electricity  —  Positive  and  Negative  —  Con- 
ductors        .  .  .  .  .  .       72-75 

Electrical  Machines  ....  75-76 

Attraction  and  Repulsion       ....       76-81 

Induction — Electropherous — Leyden  Jars  .  81-83 

Transfer  of  Electricity— Geissler  Tubes        .  .       83-89 

Magnetism     ......  89-94 

Permanent  Magnets    .....       90-92 

Electro-Magnets    .....  92-94 

Galvanism  ......     94-122 

Galvanic  Batteries  ....  96-104 

Effect  of  the  Galvanic  Current  .  .  .105-122 

Heating  and  Luminous  .  .  .         105-107 

Chemical      ......  107-110 

Mechanical         .  .  .  .  -.         110-114 

Galvanic  Induction      .  .  .  .  .114-120 

The  Ruhmkorff  Coil       .  .  .  .         117-119 

Thermo-Electricity     .....  120-121 

Animal  Electricity  .  .  .  .         121-122 


Part  II. 
CHEMISTRY— GENERAL  DEFINITIONS. 

THREE  CHARACTERISTICS  OF  CHEMICAL  AFFINITY      .  .  123-125 

INORGANIC  CHEMISTRY. 

ELEMENTS       .......  125-126 

Nomenclature — Symbols — Atomic  Weights  .         126-127 

BINARIES        .......  127-128 

Acids— Bases— Neutrals       ....         128-130 

TERNARIES      .  .  .  .  .  .  .130 

Nomenclature  of  Oxygen  and  Sulphur  Salts  .  1 30 

METALLOIDS    .......  131-177 

OXYGEN — Ozone  and  Antozone    .  .  .  .         131-138 

HYDROGEN  AND  ITS  COMPOUNDS          ....  138-143 

NITROGEN  ......        143-144 

Air — Hygrometers          .....  144-146 

Compounds  of  Nitrogen        .  .  .  .         146-151 

CHLORINE  AND  ITS  COMPOUNDS  ....  151-155 

BROMINE   .......  155 

IODINE  .  .  .  .  .  .  .156 

FLUORINE  ......        156-157 

CARBON — Its  Three  Modifications     ....  158-159 

Compounds  of  Carbon          ....         160-165 

BORON  ...  ...  165-166 

SILICON— Silica    .  166-168 


CONTENTS. 


vii 


SULPHUR        .......  168-169 

Sulphurous,  Sulphuric  and  Hydrosulphuric  Acid  .         169-173 
SELENIUM       .  .....  174 

PHOSPHORUS         ......        174-177 

METALS. 

PHYSICAL  AND  CHEMICAL  PROPERTIES  OF  METALS     .  .  177-179 

SALTS 179-180 

GROUP  I. 

POTASSIUM  ......  181-185 

SODIUM  ......         186-189 

LITHIUM      .......          189 

AMMONIUM         ......         190-191 

GROUP  II. 

BARIUM  ......         192-193 

STRONTIUM  .  .  .  .  .  .198 

CALCIUM  ,  .  .  .  .         193-196 

MAGNESIUM  ......  196-198 

GROUP  III. 

ALUMINUM,  etc.  .....         198-201 

Metals  lately  Discovered  by  Spectral  Analysis  .          202 

GROUP  IV. 
.MANGANESE       ......         202-204 

IRON  .......  205-209 

COBALT  .......  209 

NICKEL        .......  210 

CHROMIUM         ......        211-212 

ZINC  .......  212-213 

CADMIUM — COPPER        ......  214 

LEAD  .......  215-217 

BISMUTH  ......        217-218 

URANIUM     .......  218 

GROUP  V. 

TUNGSTEN — VANADIUM — MOLYBDENUM      .  .  .          219 

TELLURIUM — ARSENIC  .....        220-222 

TITANIUM— TIN       ......          222 

ANTIMONY          ......        223-224 

TANTALUM — COLUMBIUM     .....  224 

GROUP  VI. 

MKRCURY  ......         224-225 

SILVER        .......  225 

GOLD— PLATINUM          .....        226-227 

PALLADIUM  .  .  .  .  .  .  227 

IRIDIUM — OSMIUM — RUTHENIUM — RHODIUM  228 


ORGANIC  CHEMISTRY. 

CLASSIFICATION  OF  ORGANIC  BODIES  . 
I.  SACCHARINE  AND  AMYLACEOUS  BODIES 
1.  Starch 


228-230 

230 

230-231 


Vlll 


CONTENTS. 


Saccharine  and  Amylaceous  Bodies  continued. 

2.  Gum  ......  231 

3.  Lignine  ......  231-233 

Creosote— Paraffine— Coal-Tar— Naphthalin     .  233 

4.  Sugar  ......  234-235 

Fermentation      .  .  .  .  .         235-236 

Alcohols   ......  236 

Ether  .  .  .  ...  .         237-238 

Products  of  Oxidation  of  Alcohol  .  .  238-239 

Action  of  Chlorine  and  Sulphur  on  Alcohol  240 

Formic  Acid         .....  241 

II.  ETHYL— METHYL,  ETC.        ....         242-245 

Kakodyl  ......  245 

Propyl — Butyl — Amyl       ....  245 

Benzoyl— Cinnamyl— Salacyl  .  .  .  246-247 

VEGETABLE  ACIDS  .....  248 

Oxalic— Tartaric  .....  248-249 

Citric  ......         249-250 

Malic— Tannic— Gallic  .....  250-251 

ORGANIC  BASKS     .  .  .  .  .  .  251 

I.  ORGANIC  ALKALIES,  OR  ALKALOIDS        .  .  .  251-255 

II.  ARTIFICIAL  ALKALOIDS        ....         255-258 

III.  ARTIFICIAL  ALKALOIDS  HOMOLOGOUS  WITH  ANILINE     258-259 

IV.  ARTIFICIAL   ALKALOIDS    CONTAINING    SEVERAL   COM- 

POUND RADICALS      .....  259 

V.  OILS  ......  260 

(a)  Fixed  Oils,  or  Fats  .  .  .  .  261-264 

Saponification  ....  262 

Soap-Making—Candle-Making    .  .  .263 

(6)  Essential  or  Volatile  Oils  .  .  .         265-267 

(a)   Hydrocarbon  Essential  Oils     .  .  .  267 

(6)  Oxyhydrocarbon  Essential  Oils      .  .  268 

Camphors — Resins  and  Balsams      .  .  268-270 

(c)  Essential  Oils  Containing  Sulphur         .  .  270 

VI.  CYANOGEN  AND  ITS  COMPOUNDS  .  .  .  271-274 

VII.  ORGANIC  COLORING  PRINCIPLES    .  .  .  274 

Litmus — Madder — Safflower — Brazil-wood — Log- 
wood —  Quercitron  —  Fustic-wood  —  Saffron — 
Turmeric — Cochineal — Chlorophyle  .  .  274-277 

VIII.  ALBUMINOUS  BODIES        ....  277 

Protein — Albumen — Casein — Gelatin — Kreatin — 

Blood,  Etc.         .....  277-281 

APPENDIX  ......         283-297 

INDEX  ....  299-312 


NOTES  ON  CHEMISTRY. 
PART  I.   •':/>,: 


CHEMICAL  PHYSICS. 

IN  CONSEQUENCE  of  the  close  relation  existing  between 
various  physical  forces,  and  the  sciences  which  discuss 
them,  it  is  necessary  in  treating  one  subject,  to  use  some 
terms  belonging  strictly  to  other  affiliated  departments. 
Thus  in  our  present  abstract  of  Chemistry,  many  terms 
of  Mechanics,  Electricity,  Heat,  Light,  etc.,  must  be 
occasionally  employed,  and  we  therefore  place  in  this 
Introduction,  such  definitions  and  brief  explanations,  as 
may  render  such  terms,  when  afterwards  employed,  suf- 
ficiently intelligible. 

GENERAL  PROPERTIES  OF  MATTER. 

Impenetrability, — The  power  of  occupying  space  exclu- 
sively, or  so  that  another  portion  of  matter  cannot  at  the 
sa:ne  time  exist  in  the  same  place. 

Extension,  Bulk  or  Volume. — The  amount  of  space  occu- 
pied by  any  substance,  expressed  in  some  unit,  arbitrarily 
established.  See  APPENDIX,  page  283. 

(9) 


10  MECHANICAL   FORCES. 

Figure.  —  The  outline  or  boundary  of  any  body,  or  por- 
tion of  matter.  This  is  generally  expressed  by  certain 
Geometrical  terms,  such  as  Sphere,  Cube,  Pyramid,  Prism, 
Octohedron,  etc. 

Matter  is  Indestructible. — By  this  term,  we  express  the 
fact,  that  no  force  exists  in  nature,  capable  of  annihilating 
an  atom  of  matter ;  and  that,  amid  all  the  changes  going 
on  in  bodies^  by  the  operation  of  natural  causes  and  the 
.  artificial;  c^iqitions  of  our  experiments,  no  particle  per- 
ishes or  cease§  t©1  exist,  but  that  which  was  once  in  exist- 
^fldeJ-Etfa^ always,  be  found,  however  changed  in  its  form, 
*by  a  sufficiently  thorough  search. 

Example.  —  Gun-cotton  ignited,  explodes  and  disap- 
pears, being  converted  into  gas ;  but  if  the  explosion  is 
conducted  in  an  exhausted  glass  flask,  while  the  cotton 
disappears,  the  whole  apparatus  will  weigh  as  much  as 
before  the  explosion :  proving  that  no  loss  of  matter  has 
occurred. 

MECHANICAL  FORCES. 
Gravitation. 

Gravitation  is  the  force  of  attraction  which  exists  be- 
tween every  atom  in  the  universe  and  every  other  atom, 
drawing  bodies  together  with  a  force,  which  varies,  directly 
with  the  products  of  their  masses,  and  inversely  with  the 
squares  of  their  distances. 

Gravity. — This  term  is  used  to  express  that  part  of  the 
universal  gravitation,  which  exists  between  the  earth  and 
bodies  near  its  surface. 

Weight  is  the  numerical  expression  of  the  Gravity  of 
any  body  (i.  e.  the  attraction  between  it  and  the  Earth) 
reduced  to  some  arbitrary  unit,  as  the  pound,  ton,  ounce, 
grain,  etc.  See  APPENDIX,  page  28  T. 

Mass. — By  this  word  we  indicate  the  quantity  of  matter 
in  a  body.  This  is  always  expressed,  relatively,  by  the 


GRAVITATION.  11 

weight.    Thus  we  believe  that  a  body  weighing  2  Ibs.,  has 
twice  as  much  matter  in  it  as  a  body  weighing  1  Ib. 

Specific  Gravity,  or  Density. — By  this  we  indicate  the 
relative  weight  of  equal  volumes  or  bulks,  of  different  sub- 
stances. Thus,  as  a  cubic,  inch  of  iron  weighs  7  times  as 
much  as  a  cubic  inch  of  water,  we  say  that  their  densities 
are  as  7  to  1. 

In  practice  the  density  of  water  at  a  temperature  of  60°, 
is  assumed  as  the  unit  of  density  for  all  solids  and  liquids, 
and  air  at  60°  with  the  barometer  at  30  ins.  is  the  unit  for 
gases.  When,  therefore,  we  say  that  the  density  of  iron 
is  7,  of  mercury  13J,  of  gold  19,  of  alcohol  .792,  of  chlo- 
rine 2.5,  and  of  hydrogen  .069,  we  mean  that  the  first  four 
of  these  bodies  are  respectively  7,13£,  19  and  .792  times  as 
heavy  as  equal  bulks  of  water ;  and  that  the  two  Fig>  h 
last  are  respectively  2.5  and  .069,  or  l-14th  as 
heavy  as  equal  bulks  of  air. 

The  methods  for  determining  these  densities, 
it  would  be  out  of  place  to  explain  here  in  full. 
But  we  may  remark  briefly,  that  THE  DENSITY  OP 
SOLIDS  is  determined,  by  finding  their  loss  of 
weight  when  immersed  in  water,  as  is  shown  in 
the  figure,  and  then  dividing  the  whole  weight 
by  this  loss,  which  gives  the  density.  Thus,  56 
grains  of  iron  will  loose  in  water  8  grains,  then 
56  ~-  8  =  7  which  is  the  density  of  iron. 

The  Density  of  Liquids  is  found  directly  by  providing 
a  vessel  which  will  hold  a  known  weight  (say  1000  grains) 
of  water,  filling  this  with  the  liquid  to  be  examined,  and 
weighing.     Thus,  a  1000  gr.  bottle  (see  figure)    Fig-  2. 
being  filled  with  mercury,  weighs  13,500  grs.  the 
density  of  mercury  is  therefore  13?;  the  same 
bottle  filled  with  alcohol  would  have  weighed 
792  grs.,  its  density  therefore  is  .792. 


12 


COHESION. 


The  density  of  liquids  is  also 
in  practice  frequently  deter- 
mined by  the  HYDROMETER. 
Here  the  liquid  to  be  tested  is 
poured  into  a  tall  jar  (see  figure 
3)  and  a  little  tube  with  a  di- 
vided scale,  etc.  (see  figure  4) 
is  floated  in  it.  The  lighter 
the  liquid  the  lower  the  tube 
will  sink,  before  it  displaces 
enough  fluid  to  support  its 
weight,  and  thus  by  observing 
the  degree  on  the  stem  to  which 
it  sinks,  and,  referring  to  a  table 
carefully  prepared,  which  al- 
ways accompanies  the  instru- 
ment, the  density  of  the  liquid 
may  at  once  be  read  off. 

Hydrometers  are  sometimes 
used  as  a  rough  means  of  deter- 
mining the  amount  of  some  salt,  etc.  in  a  solution, 
by  its  effect  on  the  density.  In  these  cases,  the 
tables  are  often  prepared  to  indicate  this  fact,  and 
make  no  reference  to  the  density.  This,  for  exam- 
ple, is  the  case  in  the  Lactometer,  the  Yinometer, 
the  Saccharometer,  etc. 

The  Density  of  Gases  is  determined  likewise  by 
weighing  them  in  a  closed  vessel  of  known  capacity, 
with  very  careful  attention  to  the  temperature  and 
height  of  the  barometer. 

Cohesion. 

Cohesion  is  that  force  of  attraction  which  exists 
between  adjacent  particles  of  matter.  E.  g.  The  force 
which  holds  together  the  particles  of  gold,  in  a  sheet  of 
gold  leaf,  or  of  lead  in  a  bullet,  and  which  will  cause  various 


Fig.  4. 


COHESION. 


13 


parts   of  gold   leaf  firmly  pressed  Fig.  5. 

together,  or  two  halves  of  a  bullet 
lately  cut,  to  cling  with  notable  te- 
nacity; as  may  be  seen  by  the  ex- 
periment figured  in  the  drawing, 
where  two  plates  of  lead,  cleaned 
and  pressed  together,  will  support  a 
large  weight,  by  their  cohesion. 

This  force  varies  greatly  with  dif- 
ferent materials,  as  may  be  seen  by 
their  various  strength,  tenacity,  or 
resistance  to  rupture.  See  APPEN- 
DIX, page  290. 

Adhesion  is  a  term  applied  to  this  force,  for  convenience, 
when  it  acts  between  different  substances.  E.  g.  Solder 
and  Gold,  Silver,  etc. ;  Wood  and  Glue,  and  the  like.  This 
is,  however,  a  name  for  a  class  of  actions,  not  for  a  new  or 
different  force. 

Capillary  Attraction  again  is 
the  name  given  to  that  class 
of  cohesive  actions,  where  this 
force  is  exerted  between  a  solid 
of  a  tubular,  lamillar,  or  porous 
structure,  and  a  liquid,  and 
causes  a  change  of  level  in  the 
liquid,  where  it  comes  within 
reach  of  the  attraction  of  the 
solid.  Ex.  The  rising  of  oil  in 
a  lamp-wick,  of  sap  in  trees,  of 
water  in  the  earth,  etc. 

The   height  varies  with   the 

diameter  of  the  tube  and  the 

liquid  used,  as  may  readily  be 

shown  by  the  apparatus,  Fig.  6. 

2 


Fisr.  6. 


14 


COHESION. 


Fig.  7. 


Diffusion  of  Liquids  or  Gases  is  the  action  by  which 
liquids  or  gases  of  different  densities  will  mix  with  or  dis- 
solve in  each  other,  even  against  gravity.  It 
seems  a  direct  result  of  "  capillary  cohesion," 
the  porous  nature  of  liquids  and  gases  being 
taken  into  account.  E.  g.  Fill  a  glass  half  full 
of  oil  of  vitriol,  sugar  syrup  or  the  like  heavy 
liquid ;  pour  upon  it  gently  a  layer  of  water ; 
after  a  time  they  will  become  completely 
mixed.  So  if  the  vessels  a  e  connected  by  a 
fine  tube  are  filled,  (a  with  light  hydrogen, 
e  with  heavy  carbonic  acid),  they  will  soon 
be  found  to  have  completely  mingled  their 
contents. 

Osmose,  indicates  a  similar  interchange  in 
liquids,  when  it  takes  place  through  a  porous 
membrane,    as    moist   bladder,    parchment 
paper,  etc.     In  this  case  the  rate  of  transfer 
varies  greatly  in  different  substances,  and 
thus  may  be  made  a  means  of  analysis.    This 
subject  has  been  extensively  studied  by  Gra- 
ham, and  under  the  title  "  DYALYSIS,"  is  fully 
discussed  in  several  papers.    See  Franklin  Institute,  Jour- 
nal, Vol.  44,  pp.  181  and  253. 

Transpiration  of  Gases  indicates  the 
same  action  in  the  case  of  aeriform  bodies, 
a  most  striking  example  of  which  is  fur- 
nished by  the  following  experiment.  The 
porous  cup  or  battery  cell  A,  is  cemented, 
bottom,  upward  with  plaster  of  Paris,  in 
the  long  glass  funnel  B.  The  bell  jar  C. 
filled  with  hydrogen  being  then  placed 
over  A,  this  gas  will  transpire  into  the 
interior  of  A  and  B,  so  rapidly  as  to  force 
out  the  air  in  a  series  of  bubbles,  through 


REPULSION. 


15 


water  placed  in  the  little  vessel  D,  into  which  dips  the  end 
of  B.  The  bell  jar  being  then  removed,  the  hydrogen 
which  has  passed  into  A,  will  transpire  again  into  the 
outer  air,  with  such  energy,  as  to  raise  the  water  from  D, 
to  a  great  height  in  the  funnel  tube. 

The  wonderful  power  which  some  porous  bodies,  such 
as  charcoal,  coke,  platinum  black,  etc.,  possess,  of  con- 
densing gases,  seems  closely  allied  to  the  above  actions, 
and  to  result  like  them  from  cohesive  attraction. 

Repulsion. 

Repulsion  is  that  force  of  mutual  recession,  which  exists 
between  adjacent  particles  of  matter,  opposing  cohesion, 
and  greatly  affecting  its  action  in  many  cases.  This  force 
is  most  largely  exhibited  in  gases,  and  gives  to  these  bodies 

Fig.  9. 


their  almost  unlimited  powers  of  expansion.  Thus,  if  a 
flask,  containing  a  bubble  of  air,  but  otherwise  filled  with 
water  and  inverted  in  a  vessel  of  the  same,  is  placed  under 


16  HEAT. 

the  receiver  of  an  air-pump,  as  the  atmospheric  pressure  is 
removed,  the  bubble  will  expand,  until  it  fills  the  whole 
flask.  It  is  this  force  of  "  repulsion"  which  gives  to  all 
matter  its  elasticity  of  volume.  It  is  closely  related  to 
heat,  being,  perhaps,  another  consequence  of  the  same 
cause,  i.  e.  the  motion  of  all  material  atoms.  See  page  IT. 

Polarity. 

Polarity  is  that  directive  force  which  causes  adjacent 
particles  of  matter  to  assume  definite  relative  positions. 
Its  fullest  exhibition  is  found  in  the  phenomena  of  crys- 
tallization, but  it  is  the  origin  of  all  rigidity  of  form  to  be 
found  in  solid  bodies. 

The  subject  of  Crystallography  is  too  extensive  to  be 
here  discussed,  and  we  must  confine  ourselves  to  a  few 
references  and  general  statements. 

By  reason  of  polarity,  the  particles  of  solids  (and  those 
of  liquids  and  gases,  when  about  to  assume  the  solid  form) 
strive  to  arrange  themselves  in  definite  directions  as 
regards  each  other,  thus  forming  lines,  parallel  or  inclined; 
plates,  and  solids  of  geometric  forms,  as  cubes,  prisms, 
octohedrons,  and  the  like. 

Examples  of  this  action  are  furnished  in  the  snow  crys- 
tals, frost  markings  on  window-panes,  and  the  action  of  a 
slowly  evaporating  solution  of  common  salt,  etc. 

In  many  cases  this  polarity  opposes  cohesion,  and  thus 
produces  a  strain  in  the  crystallized  body,  which  gives  it  a 
power  of  affecting  light  in  a  remarkable  way.  See  page  69. 

HEAT. 

Heat  is  the  name  by  which  we  indicate  the  cause  of  a 
sensation  experienced  when  we  approach  a  fire  ;  and  of 
certain  effects,  expansion,  fusion,  etc.,  commonly  observed 
to  be  connected  with  the  same.  This  cause,  we  have  now 
every  reason  to  believe,  is  simply  a  motion,  greater  or  less, 
among  the  particles  of  bodies.  In  other  words,  the  par- 


HEAT.  17 

tides  of  a  hot  body  are  moving  more  rapidly  than  those 
of  a  cold  one,  and  from  this  more  rapid  motion,  come  all 
the  properties  by  which  hot  substances  are  distinguished 
from  cold  ones.  These  rapid  vibrations,  communicated  by 
contact  to  the  hand,  affect  the  nerves  of  touch  with  the 
"tingling"  sensation  called  "heat."  When  this  motion  of 
particles  becomes  more  rapid,  it  causes  them  to  pass 
through  greater  distances,  to  push  each  other  apart,  and 
to  strike  with  greater  force  against  the  sides  of  a  contain- 
ing vessel ;  hence  arise  the  phenomena  of  expansion. 

This  rapid  motion  in  solid  particles,  increasing,  may  at 
last  throw  them  beyond  the  range  of  the  polar  force ;  so 
making  the  solid,  liquid ;  hence  fusion.  Again,  this  same 
motion,  yet  more  increasing,  and  thus  causing  a  still  wider 
separation  between  particles,  may  drive  them  apart  beyond 
the  reach  of  Cohesion  ;  so  changing  the  solid  or  liquid  into 
a  gas  or  vapor ;  hence  vaporization,  as  in  boiling,  etc. 

Sources  of  Heat. — 1st.  The  Sun,  where  it  is  possibly 
maintained  by  the  impact  of  solid  bodies,  scattered  through 
space,  which  from  time  to  time  must  fall  in  upon  the  sun. 
The  heat  from  this  source,  shows  certain  properties  of 
intensity,  which  indicate  a  very  high  temperature  in  the 
orb  from  which  it  proceeds. 

2nd.  Mechanical  action,  Friction,  percussion,  etc.  It 
has  been  proved  by  Joule  and  others,  that  a  given  amount 
of  mechanical  action  or  motion  is  capable  of  producing  a 
given  amount  of  heat,  however  the  motion  be  applied. 
Thus,  the  force  or  motion  implied  in  the  fall  of  one  pound 
weight,  through  7?2  feet,  is  capable  of  evolving  heat 
enough  to  raise  the  temperature  of  one  pound  of  water  one 
degree.  This  is  known  as  "  the  equivalent  of  heat." 

3rd.  Electricity,  when  passing  through  a  resisting  me- 
dium. E.  g.  Lightning,  Electric  sparks,  Electric  light,  Pla- 
tinum wire,  ignited  by  a  current,  etc. 


18 


HEAT. 


4th.  Chemical  combination,  including  ordinary  combus- 
tion. Examples  of  this  are  countless ;  thus  the  mixing  of 
water  with  oil  of  vitriol,  or  with  quicklime,  or  anhydrous 
sulphate  of  copper,  develops  great  heat.  So  all  cases  of 
combustion. 

The  cause  of  the  heat  motions  in  all  these  cases  is 
plain.  In  the  1st  and  2nd,  the  great  mechanical  motion  is 
converted  directly  into  a  series  of  small  reciprocating 
motions  or  vibrations,  i.  e.  "  heat."  In  the  3rd,  the  resisted 
force,  as  it  passes  through,  causes  the  resisting  matter  to 
vibrate,  besides,  in  some  cases,  tearing  off  particles  from 
the  solid  points  between  which  it  moves,  so  giving  them 
also  vibratory  motion. 

In  the  4th,  the  different  particles  rushing  together  to 
unite,  in  like  manner  establish  vibrations,  by  a  similar 
mechanical  action. 

The  ANIMAL  HEAT  generated  in  the  bodies  of  living 
creatures,  is  simply  one  case  of  the  4th  source,  as  it  is  pro- 
duced by  union  of  the  oxygen  absorbed  by  the  blood  in 
the  lungs,  with  the  effete  matter,  exhausted  tissue,  etc., 
found  throughout  the  body.  It  is  simply  slow  combustion, 
which,  together  with  similar  actions,  such  as  the  decay  of 
-wood  in  the  air,  has  received  the  name  of  EBAMAKAUSIS. 


Fig.  10. 


Measurement  of  Heat, 

Thermometers.  —  Instruments  for  measuring 
heat.  The  air  thermometer  invented  by  Sanc- 
toria,  in  1626,  consists  of  a  glass  tube  and  bulb, 
partly  filled  with  air,  dipping  into  a  vessel  of 
water.  When  heated,  the  air  expands  and  the 
surface  of  the  water  falls  in  the  tube  ;  when 
cooled,  the  air  contracts  and  the  water  rises. 
This  instrument  is  delicate,  but  difficult  of  ad- 
justment for  comparison  of  results. 


HEAT.  19 

The  spirit  thermometer,  invented  by  a  member  of  the 
Florentine  Academy,  consists  of  a  capillary  glass  tube, 
with  a  bulb,  partly  filled  with  alcohol,  otherwise  vacuous, 
and  hermetically  sealed,  and  having  a  scale  attached, 
divided  into  degrees,  as  will  be  presently  described. 

This  instrument  is  much  used  for  very  low  tempera- 
tures, but  is  useless  above  150°  F.,  as  alcohol  boils  about 
173°  F. 

The  mercurial  thermometer  invented  by  Roemer.  This 
is  exactly  like  the  last,  mercury  being  substituted  for  alco- 
hol. In  order  that  various  instruments  may  be  made  to 
accord,  two  fixed  points  have  been  settled  upon,  the  melt- 
ing point  of  ice,  and  the  boiling  point  of  water.  The 
height  of  the  mercury  corresponding  to  these  being  ascer- 
tained, the  space  between  may  then  be  divided  into  de- 
grees, according  to  one  of  three  scales  now  in  use,  the 
Fahrenheit,  the  Centigrade,  the  Reaumur.  The  first,  F., 
divides  the  space  into  180°,  numbering  the  first  32°  and 
the  last  therefore  212°  (32  -f  180  =  212.) 

The  second,  C.,  divides  it  into  100°,  numbering  the  first 
0°  and  last  100°. 

The  third,  R.,  divides  it  into  80°,  numbering  the  first  0° 
and  last  80°. 

To  convert  degrees  of  one  of  these  scales  into  those  of 
another,  the  following  formula  may  be  used. 


Cent.  =  |R.  =  §  (F.— 32) 
Reau.=  Jc.=:4(F>_82) 
Fahr.  =  |  C.  -f  32  =  |  R.  +32 


A  table  showing  at  a  glance 
the  corresponding  degrees,  will 
be  found  in  the  APPENDIX,  p. 291. 


Above  and  below  the  fixed  points,  the  degrees  are 
marked  off  by  simple  measurement,  and  comparison  with 
those  between.  Degrees  below  the  0°  of  each  scale  are 
numbered  progressively  downwards,  and  are  distinguished 
by  the  sign  minus  ;  thus  the  freezing  point  of  mercury  is 
—  40°  F. 


20  HEAT. 

Specific  Heat. — We  might  suppose  that  the  same  amount 
of  heat  being  applied  to  different  bodies  would  raise  them 
all  to  the  same  temperature ;  but  this  is  not  so.  From 
the  different  arrangement  of  particles  in  various  bodies, 
some  require  more  force  than  others  to  develop  a  given 
velocity  of  movement.  This  difference  of  capacity  for 
becoming  heated,  we  call  Specific  Heat.  In  expressing  it 
relatively,  we  assume  water  (which  has  the  greatest  of  all 
bodies),  as  the  unit. 

Specific  Heat  of  Solids  and  Liquids. 

Water 1.0000 

Alcohol,  sp.  gr.  =0.81 0.7000 

Nitric  Acid,  sp.  gr.  ==1.29895 0.6613 

Wood,  in  the  average 0.4800 

Sulphuric  Acid,  sp.  gr.  1.605 0.3346 

Sweet  Oil 0.3096 

Lime 0.2169 

Sulphur 0.2085 

Glass 0.1929 

Cobalt 0.1498 

Iron 0.1098 

Nickel 0.1035 

Copper 0.0940 

Tellurium 0.0912 

Antimony 0.0507 

Zinc 0.0927 

Tin 0.0475 

Platinum 0.0344 

Bismuth 0.0298 

Mercury 0.0290 

Gold 0.0288 

Lead 0.0281 

The  high  specific  heat  of  water  is  of  great  value  in 
moderating  the  extremes  of  temperature  and  equalizing 
climate  in  the  neighborhood  of  large  masses  of  water. 
The  excess  of  heat  is  there  absorbed  without  rendering 
the  water  proportionately  hot,  and  again  emitted,  without 
corresponding  fall  of  temperature. 


HEAT. 


21 


Specific  heat  of  Gases  and  Vapors  as  compared  with  equal  weight 
of  Water. 


Water 1.00000 

Air 0.23741 

Oxygen 0.21751 

Hydrogen 3.40900 

Nitrogen 0.24380 

Chlorine 0.12099 

Bromine 0.05552 

Carbonic  Acid 0.20246 

Carbonic  Oxide 0.24500 

Nitrous  Oxide 0.24470 

Nitric  Oxide 0.23173 


Marsh  Gas 0.59295 

Ether  Vapor 0.47966 

Alcohol  Vapor 0.45341 

Olefiant  Gas 0.40400 

Sulphurous  Acid 0.15531 

Hydrochloric  Acid 0.18521 

Sulphuretted  Hydrogen  0  24218 

Ammonia 0.50836 

Turpentine  Vapor 0.50610 

Bisulphide  of  Carbon...  0.15696 


A  curious  connection  between  the  specific  heat  of  bodies 
and  their  atomic  weights  was  first  announced  by  Dulong 
and  Petit,  and  has  been  confirmed  by  Regnault,  namely, 
that  the  specific  heats  of  elements  are  inversely  as  their 
atomic  weights  ;  or  that  the  products  of  these  two  quanti- 
ties are  constant.  According  to  the  experiments  of  Reg- 
nault, however,  this  "  constant "  may  vary  between  2.95 
and  3.41. 

We  should,  from  this  law,  conclude  that  the  same 
amount  of  heat  is  needed  to  raise  an  atom  of  any  element 
through  a  given  number  of  degrees. 

In  compound  bodies  the  same  law  holds  good,  except 
that  the  constant  varies  with  different  classes  of  bodies. 
Thus,  for  the  protoxides  it  is  5.64,  for  the  sesquioxides 
13.6,  for  the  sulphides  4.92,  for  the  carbonates  10.15,  etc. 

Effects  of  Heat.  I.  Expansion.  —  All  bodies,  with  cer- 
tain exceptions  to  be  presently  noticed,  expand  with  an 
increase  of  temperature,  and  contract  with  a  loss  of  heat. 
This  expansion  is,  however,  very  various  in  different 
bodies,  as  will  appear  from  the  following  table : 


HEAT. 


Linear  Expansion  of  Solids  between  32°  and  212°  F.  for  each  degree. 


White  Glass 0.00000478 

Platinum 0.00000491 

Untempered  Steel...  0.00000600 

Cast  Iron 0.00000618 

Wrought  Iron 0.00000656 

Tempered  Steel 0.00000689 

Gold...                     ..  0.00000815 


Copper 0.00001092 

Bronze 0.00001009 

Brass,  Cast 0.00001043 

Silver 0.00001060 

Tin 0.00001207 

Lead 0.00001850 

Zinc...,  ..  0.00001633 


Cubic  Expansion  of  Liquids  between  32°  and  212°  for  each  degree  F. 

Mercury 0.018018 

Water 0.046600 

Sulphuric  Acid 0.06000 

Oil  of  Turpentine  or 

Ether....  ..  0.0003890 


Common  Oil 0.0004444 

Alcohol    or    Nitric 
Acid...  ..  0.0005555 


Cubic  Expansion  of  Gases  between  32°  and  212°  for  each  degree  F. 


Air 0.00203111 

Hydrogen 0.00203766 

Nitrogen 0.00203788 

Sulphurous  Acid 0.00203866 


Hydrochloric  Acid...  0.00204511 

Cyanogen 0.00204561 

Carbonic  Acid...       ..0.00204977 


From  this  it  appears  that  the  expansion  of  various 
gases  is  practically  the  same. 

At  temperatures  above  and  below  those  mentioned  in 
the  foregoing  tables,  the  rate  of  expansion  varies  slightly 
with  different  substances,  increasing  with  the  rise  in  tem- 
perature, and  decreasing  with  the  reverse ;  but  these 
changes  are  not  of  sufficient  importance  to  be  here  dwelt 
upon. 

A  great  variation  is  also  found  at  those  temperatures 
where  the  body  changes  its  form,  as  from  liquid  to  solid ; 
and,  in  the  case  of  water,  this  amounts  to  a  reversal  of 
the  rule.  Between  the  melting  point,  32°  and  40°,  water 
contracts  as  it  grows  hotter,  so  that  its  maximum  density 
is  at  that  point,  i.  e.  40° ;  growing  less  by  change  of  tem- 
perature either  way. 


HEAT.  23 

The  tables  above  given  hold  good  both  ways ;  bodies 
contracting  when  lowered  in  temperature,  just  as  they 
expand  when  raised. 

The  close  equality  in  expansion  of  glass  and  platinum 
is  of  great  value,  enabling  us  in  constructing  apparatus 
to  directly  weld  or  join  these  substances  without  risk  of 
fracture  through  change  of  temperature. 

Applications  of  expansion  and  contraction  are  countless. 
Shrinking  tires  on  wheels,  iron  wheels  on  axles,  etc. ;  draw- 
ing up  the  falling  wall  of  the  Conservatoire  des  Arts  et  Me- 
tiers; compensating  pendulums  and  balance-wheels  ;  ther- 
mometers of  all  kinds ;  testing  strength  of  steam  boilers 
easily  and  safely,  by  filling  full  with  water,  closing  all 
valves,  attaching  pressure  guage,  and  warming ;  air  en- 
gines, etc. 

Effects  of  Heat.  IE.  Fusion.  —  Solid  bodies  heated 
to  a  certain  point,  begin  to  change  their  form,  and  to 
become  liquid,  excepting,  of  course,  such  compounds  as 
suffer  decomposition  before  this  fusing  point  is  reached. 
The  temperature  at  which  this  change  takes  place  differs 
greatly  with  different  bodies,  but  is  unchangeable  for  each, 
except  as  it  is  slightly  affected  by  great  changes  of  pres- 
sure. Thus,  under  pressure  of  100  atmospheres,  the 
melting  point  of  paraffine  is  raised  6'3°,  and  of  spermaceti 
3'6°  F.  The  melting  point  of  ice,  however,  is  lowered 
by  pressure,  so  that  it  may  become  liquid  under  pressure, 
•  and  solidify  on  the  relief  of  the  same.  This  explains  the 
phenomena  of  "regellation,"  and  the  motion  of  glaciers. 
See  Tyndale  on  Heat  as  a  Mode  of  Motion,  page  208. 

The  fusing  point  of  different  substances  will  be  given 
hereafter,  where  their  various  properties  are  described 
under  the  head  of  Chemistry. 

Latent  Heat  of  Liquids.  —  We  observe  by  experiment 
that  a  large  amount  of  heat  is  required  to  convert  a  solid 
into  a  liquid,  without  producing  any  effect  in  changing  its 


24  HEAT. 

temperature.  Thus,  if  a  pound  of  ice  at  32°  is  mixed 
with  a  pound  of  water  at  176°,  the  ice  will  be  melted, 
and  we  shall  have  two  pounds  of  water  at  32° ;  all  the 
additional  heat  in  the  water  (144°)  having  been  absorbed 
by  the  ice,  without,  however,  any  increase  to  its  tempera- 
ture, but  with  simply  a  change  in  its  state.  Heat  so 
absorbed  we  call  •"  latent  heat." 

This  phenomenon  should  be  expected  from  our  theory. 
A  certain  amount  of  force,  in  the  shape  of  heat -motions, 
or  vibrations,  must  be  expended  in  overcoming  the  polar 
force  between  the  particles,  and  thus  changing  the  state 
of  the  body. 

This  latent  heat  varies  with  different  bodies,  as  will  be 
seen  from  the  following  table,  in  which  the  number  shows 
how  many  degrees,  the  heat  absorbed  in  fusing  the  given 
substance,  would  raise  the  same  after  liquefaction. 


Water 142.65 

Nitrate  of  Soda 112.98 

Zinc 50.63 

Silver 37.92 

Tin 25.65 

Cadmium.  ..  ..  24.58 


Bismuth 22.75 

Sulphur 16.86 

Lead 9.66 

Phosphorus 9.05 

Fusible  metal* 8.10 

Mercury 4.93 


This  latent  or  absorbed  heat,  is  absolutely  necessary  to 
the  change  of  form  from  solid  to  liquid  ;  hence  if  in  any  way 
this  change  is  effected  without  giving  this  required  heat, 
the  body  will,  or  must,  lose  a  corresponding  amount  of  its 
own  heat  or  heat  motion,  having  in  this  case  performed 
this  work  of  change,  by  and  at  the  expense  of  its  own  inter- 
nal motive  power  or  heat  vibrations,  and  it  must  therefore 
fall  in  temperature.  This  is  the  theory  of  "  FREEZING  MIX- 
TURES." Certain  bodies  if  mingled  become  liquid,  by  rea- 
son of  certain  attractions  among  their  particles,  they  con- 
sequently absorb  heat  motions  in  effecting  this  change,  and 
fall  in  temperature.  Some  of  these  bodies,  and  the  descents 

*  1  Lead,  1  tin,  and  4  bismuth. 


HEAT.  25 

accomplished  by  rapidly  mixing  them,  are  given  in  the 
following  table. 

Sulphate  of  Soda 8  | 

,    .  .         Hydrochloric  Acid 5J 

Pounded  ice  or  snow 2} 

-    /•  -4-  oJt     t»0  U. 

Common  salt 1 


Sulphate  of  Soda 3) 

Dilute  Nitric  Acid 2j  + 

Sulphate  of  Soda 6  j 

Nitrate  of  Ammonia 5  >•  +  50°  to  — 14. 

Dilute  Nitric  Acid 4) 

Phosphate  of  Soda 9) 

Dilute  Nitric  Acid./ « j  +  50°  to  ~20- 


Such  preparations  as  the  above  are  often  used  ;  in  chem- 
ical operations,  where  a  very  low  temperature  is  required, 
as  in  preparing  liquid  sulphurous  acid,  in  surgery,  and  in. 
culinary  processes,  as  in  the  preparation  of  ice-cream.  In 
all  cases  the  more  finely  the  ingredients  are  pulverized, 
and  the  more  thoroughly  they  are  mixed,  the  lower  the 
temperature  reached.  It  must  also  be  remembered  that 
the  fluid  obtained,  is  far  colder  than  the  solids  employed, 
and  is  indeed  the  efficient  source  of  refrigeration  and  must 
not  therefore  be  drained  off  or  allowed  to  escape,  until  it 
has  done  its  work. 

Freezing.  Congellation. — As  we  might  naturally  expect, 
when  the  action  last  discussed  is  reversed,  and  heat  is 
abstracted  from  a  liquid,  it  will  at  a  certain  point,  begin  to 
change  its  form  and  become  solid.  We  might  also  sup- 
pose that  the  point  at  which  this  change  took  place,  in  any 
substance,  was  the  same  either  way.  This  is  indeed  so  as 
a  rule,  but  not  under  all  conditions.  Thus,  if  water,  de- 
prived of  air,  is  kept  absolutely  at  rest,  it  may  be  cooled 
to  11°  without  freezing;  then,  the  least  shock  or  jar,  will 
cause  it  to  freeze  in  an  instant.  So  a  concentrated  hot 
'3 


26  HEAT. 

solution  of  sulphate  of  soda,  cooled  at  rest  and  out  of  con- 
tact with  air,  remains  liquid  indefinitely,  until  shaken  or 
exposed  to  the  atmosphere. 

In  becoming  solid,  the  liquid  develops  as  much  heat  as 
it  destroyed  in  becoming  liquid ;  this  is  shown  in  the  case 
of  the  water  by  the  immediate  rise  in  temperature  of  the 
whole  material  to  32°,  on  the  freezing  of  part,  and  in  the 
case  of  the  sulphate  of  soda,  by  a  notable  heating. 

In  all  ordinary  cases,  moreover,  we  find  that  while  we 
are  freezing  or  solidifying  any  liquid,  its  temperature  does 
not  fall,  during  the  whole  process,  though  heat  is  being 
abstracted  from  it  at  a  rapid  rate. 

Expansion  in  Freezing.— At  the  moment  of  passing  from 
the  liquid  to  the  solid  state,  most  substances  expand.  This 
is  very  notable  in  water,  which  increases  to  1.075  times 
its  bulk  at  40° ;  hence  ice  floats  on  water.  This  expan- 
sion takes  place  with  such  force  as  to  burst  even  strong 
iron  vessels,  and,  under  very  heavy  pressure  restraining 
this  expansion,  according  to  M.  Mousson,  water  will  not 
entirely  solidify. 

Like  water,  cast-iron,  antimony  and  bismuth,  expand  in 
solidifying ;  mercury,  phosphorus,  stearine,  etc.,  contract. 

Effects  of  Heat.  III.  Vaporization.  —  Liquids  when 
heated  to  a  certain  point,  begin  to  change  their  state,  and 
to  pass  into  the  condition  of  gases.  The  temperature  at 
which  this  change  takes  place,  differs  greatly  with  differ- 
ent substances,  though  it  is  the  same  for  the  same  body, 
under  the  same  conditions  ;  but  it  is  largely  affected  by 
changes  of  pressure,  the  nature  of  the  containing  vessel, 
etc.  The  phenomenon  alluded  to,  is  commonly  called  BOIL- 
ING, and  the  temperature  at  which  this  action  begins,  is 
called  the  "boiling  point."  The  boiling  points  of  various 
bodies  will  be  stated  hereafter,  in  connection  with  their 
other  properties. 


HEAT. 


2t 


The  effect  of  a  change  in  pressure,  on  the  boiling  point 
of  water,  will  be  seen  from  the  following  table. 

Water,  boiling  in  the  open  air,  is  under  a  pressure  of 
about  15  Ibs.  per  sq.  inch  (or  such  as  would  be  given  by  a 
column  of  mercury  30  inches  high),  due  to  the  weight  of 
the  atmosphere.  Under  this  condition  its  boiling  point  is 
212°  F. 


Under  pressure  of 

Its  boiling 
point  in 

0.200  ins.  of  mercury  =       0.098lb8.pr.sq.in.=  0.006  atmospheres  32° 

0.524 

=      0.257 

=  0.017 

60° 

1.000 

=      0.490 

=  0.033 

80° 

1.860 

==      0.911 

=  0.062 

«      100° 

.7420 

=      3.636 

=  0.247 

«       150° 

15.150 

=      7.420 

=  0.505 

"       180° 

30.000 

=    14.700 

=  1.000 

"      212° 

61.200 

=    30. 

2 

"      251.6° 

91.800 

=    45. 

=  3. 

"      276.4° 

122.400 

=    60. 

=  4. 

«      295.6° 

153.000 

=    75. 

=  5. 

«'      311.2° 

183.600 

=    90. 

=  6. 

«<       324.3° 

214.200 

=  105. 

=  7. 

"       335.8° 

244.8 

=  120. 

=  8. 

"       345.8° 

275.4 

=  135. 

=  9. 

"       355.0° 

306.0 

=  150. 

=10. 

"       363.4° 

387.2 

=  180. 

=12. 

"      378.4° 

612.0 

=  300. 

=20. 

"      420,3° 

1223.0 

==  600. 

=40. 

"       487.0° 

2038. 

=1000. 

=66.6 

"      548.0° 

From  this  table,  various  conclusions  may  be  drawn. 
The  boiling  point  varies  less  and  less  with  the  pressure, 
as  it  ascends.  Thus,  the  change  of  less  than  one  atmos- 
phere makes  a  difference  of  180°  in  the  boiling  point 
between  32°  and  212°,  while  it  makes  a  change  of  but  39° 
between  212°  and  251°,  and  of  but  25°  between  251°  and 
276°,  etc.  These  points  of  pressure  and  temperature  being 
inseparable,  one  may  serve  as  a  measure  of  the  other. 


28 


HEAT. 


Fig.  11. 


A  liquid  inclosed  in  a  tight  vessel,  will  generate  a  pres- 
sure corresponding  to  its  temperature.  If  in  any  way 
this  pressure  is  relieved,  the  liquid  will  boil  violently, 
because  heated  above  its  boiling  point  for  this  lesser  pres- 
sure. This  is  well  illustrated  by  the  Culinary  Paradox. 
Here  a  glass,  containing  water  in 
the  act  of  boiling,  is  corked  and  in- 
verted. If  now  cold  water  is  poured 
over  the  flask,  the  vapor  or  steam 
contained  will  be  condensed,  the 
pressure  thus  relieved,  and  the  water 
made  to  boil  violently.  The  same 
thing  is  proved  by  various  experi- 
ments in  freezing  by  evaporation,  to 
be  presently  described.  This  fact  is 
again  usefully  applied  in  the  manu- 
facture of  sugar. 

The  pressure  of  the  atmosphere 
varies  at  different  heights ;  this  ef- 
fects the  boiling  point  of  water,  and  thus  we  may,  with 
a  thermometer,  measure  the  height  of  various  locations. 
A  change  in  boiling  point  of  1°  indicates  a  change  in 
height  of  600  feet.  On  Mt.  Blanc  water  boils  at  183°, 
and  at  Quito  at  194°. 

For  tension  of  various  vapors  at  different  temperatures, 
see  Regnault's  Tables,  Fr.  Inst.  Jour.,  Yol.  XV.,  pp.  136, 
207,  278,  356,  and  437  ;  Yol.  XVI.,  pp.  48,  115,  186,  257, 
328,  and  388;  Vol.  XVII.,  p.  50,  114,  and  190  ;  Vol.  XL., 
p.  241. 

The  change  in  volume  which  accompanies  the  change 
of  a  liquid  to  the  gaseous  form,  is  very  great,  varying, 
however,  with  the  pressure  ;  the  volume  of  steam,  like 
that  of  any  other  gas,  varying  inversely  with  the  pressure 
applied.  At  the  ordinary  atmospheric  pressure,  however, 
water  expands  1694  times  in  becoming  steam.  In  round 


HEAT.  29 

numbers,  a  cubic  inch  of  water  makes  a  cubic  foot  of 
steam. 

The  nature  of  the  vessel  containing  the  liquid,  has  a 
marked  effect  upon  its  boiling.  A  vessel  offering  strong 
adhesion  to  the  liquid,  and  no  points  from  which  bubbles 
of  steam  can  be  readily  disengaged,  raises  the  boiling 
point,  and  renders  that  action  violent  and  spasmodic. 
Thus,  water  in  a  smooth  and  clean  glass  flask,  may  be 
raised  to  222°  before  it  boils. 

A  few  scraps  of  metal,  or  even  angular  bits  of  glass, 
will  lower  the  boiling  point  to  its  normal  state,  and  mode- 
rate the  violence  of  the  action. 

Water  deprived  of  air,  boils  also  with  difficulty  and  vio- 
lence. In  fact,  Grove,  from  many  experiments,  concludes 
that  if  water  could  be  entirely  deprived  of  all  gas  (a  re- 
sult never  yet  attained),  it  would  not  boil  till  heated  hot 
enough  to  cause  its  decomposition.  See  Proceedings  of 
the  Royal  Institution,  1864,  p.  166. 

Latent  Heat  of  Gases.  —  As  in  the  conversion  of  solids 
into  liquids,  so  also  in  the  conversion  of  liquids  into 
gases,  we  observe  that  a  large  amount  of  heat  is  ex- 
pended in  effecting  this  change,  without  any  influence 
upon  the  temperature  of  the  body  in  question.  This  fact 
likewise  accords  with  our  theory,  as  before.  The  lost  or 
latent  heat  is  but  so  much  heat-motion  expended  in  over- 
coming the  cohesive  force,  which  kept  the  body  in  its 
liquid  form. 

The  latent  heat  of  different  gases  or  vapors,  varies 
greatly,  that  of  water  or  steam  being  the  highest.  Thus, 
the  heat  required  to  convert  one  pound  of  water  into 
steam,  would  raise  a  pound  of  water  otherwise  through 
912  degrees.  With  other  bodies  it  is  as  in  the  table. 


Water 972. 

Alcohol 374. 

Acetic  Acid 183. 

3* 


Ether 162. 

Turpentine 133. 


30  HEAT. 

Where  differences  of  pressure  are  introduced,  the  latent 
heat  varies,  decreasing  with  the  increase  of  pressure,  and 
consequent  rise  of  the  boiling  point. 

As  we  have  already  noticed  with  the  latent  heat  of 
liquids,  so  with  gases,  if  the  change  of  state  is  accom- 
plished without  a  supply  of  extraneous  heat,  heat  must 
be  supplied  and  lost  by  the  changing  body  itself.  We 
may  regard  the  liquid  particles  as  possessing  motions  or 
heat  vibrations,  tending  to  throw  them  beyond  the  range 
of  cohesion,  but  not  yet  sufficiently  powerful  to  overcome 
that  force.  Hence,  they  vibrate  within  their  boundaries 
like  a  pendulum,  restrained,  but  without  loss  of  motion, 
thus  preserving  their  temperature.  If  now  a  little  addi- 
tional force  is  given  them,  just  enough  (with  what  they 
possessed)  to  overcome  cohesion,  they  break  their  bounds, 
but,  in  doing  so,  have  spent  their  force,  and  (like  a  pen- 
dulum which  has  just  been  able  to  break  from  its  sup- 
port) fall  motionless,  or  nearly  so,  into  their  new  state. 
In  other  words,  lose  much  of  their  heat  motion  and  be- 
come "cold."  All  cooling  or  freezing  by  evaporation  is 
of  this  kind.  A  striking  instance  is  as  follows : 

If  a  little  water  in  a  small  dish  is  supported  over  a 
larger  one  containing  oil  of  vitriol,  both  being  under  the 
exhausted  receiver  of  an  air-pump ;  the  boiling  point  of 
the  water  will  be  so  low,  under  the  diminished  pressure, 
that  this  action  will  go  on  at  the 
ordinary  temperature,  and  (the  va- 
por formed  being  absorbed  by  the 
oil  of  vitriol)  will  continue.  But 
the  water,  passing  into  vapor, 
destroys  or  renders  latent  much 
heat  motion,  it  therefore  becomes 
cold,  and  cools  the  water  from 
which  it  rises,  until  finally  the 
latter  is  frozen  by  its  own  evaporation.  We  may  thus 


HEAT. 


31 


have  the  strange  anomaly,  of  water,  at  once  boiling  and 
freezing,  practically  realized. 

On  the  same  principle  operates  the  Criopherous  of 
Wollaston,  consisting  of  two  connected  bulbs  containing 
some  water,  and  exhausted  of  air.  All  the  water  being 
turned  into  one  bulb,  and  the  other  placed  in  a  freezing 
mixture ;  the  vapor  within  is  thus  condensed  as  fast  as  it 
forms,  and  the  water  from  which  it  rises  is  quickly  frozen, 
as  before,  by  its  own  evaporation. 

A  more  practical  application  of  the  same  general  prin- 
ciple, is  furnished  in  the  freezing  apparatus  of  Carre. 

Fig.  13. 


This  consists  of  two  strong  wrought-iron  vessels,  A  and 
B,*  connected  by  a  tube  C,  the  whole  exhausted,  and 
closed  air-tight.  A  contains  strong  aqua  ammonia,  and 
is  placed  in  a  furnace,  where  it  is  heated  until  a  thermom- 
eter, set  in  an  oil  tube  D,  indicates  a  temperature  of 
270°  F.,  B,  in  the  meantime,  being  immersed  in  water  at 
the  ordinary  temperature.  By  this  means  the  ammonia 
is  driven  out  of  the  water  in  A,  and  is  condensed  under 
a  pressure  of  6^  atmospheres  into  a  liquid  form  in  B.  A 

*  B.  is  shown  in  section. 


32  HEAT. 

is  then  removed  from  the  furnace  and  plunged  into  the 
water  which  before  surrounded  B,  while  the  vessel  con- 
taining the  substance  to  be  frozen  is  placed  in  the  opening 
in  B,  a  little  alcohol  being  poured  into  the  space  between  to 
prevent  it  from  freezing  fast.  The  pressure  being  relieved 
by  the  cooling  of  A,  the  condensed  ammonia  in  B  boils, 
and  its  vapor  being  rapidly  absorbed  in  the  now  cold 
water  in  A,  this  action  is  kept  up,  causing  a  rapid  loss 
of  heat  in  B.  With  the  small  apparatus  sold  in  Paris  for 
100  francs,  the  heating  occupies  about  30  minutes,  after 
which,  with  care,  two  cans  full  of  water  (about  2  quarts) 
may  be  frozen  into  solid  ice.  This  apparatus  may  be 
applied  to  domestic  uses.  On  the  large  scale  it  has  been 
so  constructed  as  to  be  continuous  in  its  action,  and  has 
been  reported  upon  favorably  by  the  French  Academy. 
See  Journal  of  the  Franklin  Institute  of  Pennsylvania, 
Vol.  48,  page  109. 

Evaporation  is  the  term  by  which  we  designate  the 
gradual  vaporization  of  a  liquid  at  its  surface,  which  may 
take  place  at  any  temperature.  Example,  Drying  of  a 
wet  cloth.  This  action,  like  vaporization,  implies  a  great 
absorption  of  latent  heat.  Thus  masses  of  water  are  but 
little  affected  by  the  heat  of  summer,  and  the  body  in 
like  manner  by  the  evaporation  of  perspiration  from  its 
surface  is  saved  from  an  injurious  elevation  of  its  tempera- 
ture, even  when  exposed  to  intense  heat.  Thus  Dr. 
Fordice,  Sir  Joseph  Banks,  and  others,  sat  for  half  an 
hour  in  an  oven  with  a  joint  of  meat  which  was  cooked 
during  the  time. 

Condensation. — When  the  action  described  in  vapori- 
zation is  reversed,  and  the  temperature  of  a  gas  is 
lowered,  a  point  may  at  last  be  reached,  at  which  it  will 
change  its  state,  and  become  liquid.  This  change  of  a 
gas  into  a  liquid  by  loss  of  heat  is  called  CONDENSATION  : 
when  assisted  by  pressure,  it  is  termed  LIQUEFACTION. 


HEAT.  33 

The  temperature  at  which  this  change  takes  place  is 
identical  with  that  at  which  the  reverse  change  happens, 
in  each  substance  ;  in  fact  its  boiling  point,  and  as  might 
be  expected,  the  latent  heat  expended  in  the  reverse 
change  is  redeveloped  in  this.  Thus  a  pound  of  steam, 
at  212°,  would  give  out  in  passing  into  the  state  of  water, 
at  the  same  temperature,  as  much  heat  as  would  raise  a 
pound  of  water  through  972°,  or  972  pounds  of  water 
through  1°. 

Distillation. — By  combining  the  two  processes  of  vapo- 
rization and  condensation,  we  may  effect  the  .separation 
of  substances  having  different  boiling  points,  when  these 
are  mixed.  This  operation  is  called  distillation.  We 
place  the  mixture  in  a  closed  vessel  called  a  retort  or 
still,  and  there  heat  it,  until  the  more  volatile  body  is 
vaporized ;  the  vapor  formed  is  carried  directly  into  a 
condenser,  receiver,  worm,  or  the  like,  where  it  is  cooled, 
and  so  rendered  liquid.  The  more  volatile  body  is  thus 
separated  from  that  which  is  less  so,  and  which  remains 
in  the  retort  or  still,  not  being  heated  to  its  boiling  point. 
It  must  be  remembered,  however,  that  the  less  volatile 
body  will,  in  these  conditions,  evaporate,  and  that  thus 
portions  will  pass  over  with  the  other.  A  complete 
separation  cannot,  therefore,  be  thus  obtained.  Alcohol 
will,  for  example,  carry  over  with  it  at  least  fifteen  per 
cent,  of  water,  and  mercury  a  notable  quantity  of  gold, 
even,  as  well  as  other  metals. 

Sublimation  is  the  term  applied  to  a  like  action,  when  the 
substance  treated  is  a  solid,  which  passes  into  the  gaseous 
state,  directly  or  after  fusion,  and  likewise  back  into  the 
solid  form.  Example,  purifying  sulphur,  iodine,  etc. 

Transfer  of  Heat.  —  Heat  may  pass  from  place  to  place, 
and  body  to  body,  in  one  or  other  of  three  ways,  i.  e.,  by 
Conduction,  Convection,  or  Radiation. 

Conduction  is  the  transfer  of  heat  by  means  of  particles 


34 


HEAT. 


in  contact.  E.  g.  The  end  of  a  poker  being  put  in  the 
fire,  the  handle  will,  in  time,  become  heated,  by  conduc- 
tion, through  the  iron  itself.  This  power  of  conduction 
belongs  chiefly  to  solids,  and  varies  greatly  in  different 
substances,  as  will  appear  from  the  following  table  : 

Table  of  conducting  powers  of  Solids. 


Gold 1,000 

Silver  973 

Copper  898 

Iron 374 

Zinc...  .    363 


Tin 303.9 

Lead 179.6 

Marble 23.6 

Porcelain 14.2 

Clay 11.4 


Fig.  14. 


From  this  it  follows,  that  whenever  we  wish  to  pro- 
mote the  transfer  of  heat,  we  should  use  good  conductors, 
as  in  culinary  vessels,  steam  boilers,  and  the  like  ;  while 
for  the  prevention  of  this  transfer,  bad  conductors  should 
be  employed,  as  in  ice-houses,  winter  clothing,  handles  of 
tea-kettles,  etc. 

Conduction  takes  place  with  great  dif- 
ficulty IN  LIQUIDS.  Thus,  if  an  air  ther- 
mometer is  placed  in  a  liquid,  as  in  the 
drawing,  and  this  is  strongly  heated  at 
the  surface,  by  a  hot  iron,  very  little 
effect  will  be  produced  upon  the  ther- 
mometer, at  a  short  distance  below. 

The  conducting  power  of  gases  is  pro- 
bably even  less  than  that  of  liquids, 
though  owing  to  their  great  mobility  and 
diathermancy,  this  is  hard  to  demonstrate 
directly.  The  efficiency  of  double  sashes, 
double  walls,  in  iron  furnaces,  and  the 
like,  however  practically  indicates  this, 
as  does  also  the  following  phenomenon. 

The  spheroidal  state.  —  By  this  term  we  indicate  the 
condition  of  a  liquid,  when  .thrown  upon  a  solid  body, 
heated  considerably  above  the  boiling  point  of  the  former; 


HEAT. 


35 


Fig.  15. 


when  it  is  lifted  out  of  contact  with  the  solid,  by  vapor 
first  formed,  and  then  remains  floating  upon  this  cushion 
of  steam,  which  is  supplied  as  it  escapes,  by  evaporation 
at  the  lower  surface,  and  protects  the  liquid  from  any 
great  accession  of  heat,  so  that  this  is  never 
raised  to  its  boiling  point.  This  is  well  shown 
by  dropping  water  over  an  inverted  red-hot 
platinum  dish,  properly  focused  in  a  magic 
lantern,  and  watching  the  image  on  a  screen. 
If  liquid  sulphurous  acid  is  employed,  water 
may  be  frozen  in  a  red-hot  crucible ;  or  with 
solid  carbonic  acid  and  ether,  mercury  even  can 
be  frozen  in  the  same  situation.  The  non-con- 
ducting state  of  the  vapor  is  clearly  necessary 
to  the  above  condition. 

By  reason  of  this  same  action,  the  hand  is  pro- 
tected if  placed  for  a  moment  in  a  stream  of 
molten  iron,  gold,  or  the  like  ;  the  skin  being 
shielded  by  a  non-conducting  layer  of  vapor  from  the  burn- 
ing fluid.  This  fact  explains  some  conjurers  feats,  and 
many  of  the  famous  ordeals. 

For  the  production  of  this  spheroidal  state,  a  certain 
temperature  is  required ;  hence  the  value  of  the  test  ap- 
plied by  the  laundress  to  her  flat-irons.  If  the  water  runs 
off  in  drops  without  boiling,  the  iron  is  hot  enough. 

Convection.  —  This  term  describes  the  transfer  of  heat 
by  particles  in  motion  —  as  thus:  Heat  being* applied  to 
the  bottom  of  a  vessel  of  water,  the  lower  particles  of 
the  fluid  become  hot,  are  consequently  dilated,  and  giving 
place  to  cold,  and  therefore  denser  particles  rise,  carrying 
their  heat  into  other  parts  of  the  vessel. 

This  mode  of  transfer  can  only  exist  in  liquids  and  gases, 
whose  particles  are  mobile,  and  is  in  fact  the  means  by 
which  masses  of  such  bodies  become  heated  through- 
out. The  currents  thus  established  are  easilv  shown 


36 


HEAT. 


in   water,   by   a    little   powdered    amber   mixed   in  the 
liquid,  and  in  air  by  smoke  or  dust. 


Fig.  16. 


In  all  cases  of  heating  such  sub- 
stances on  the  large  scale,  as  in  steam 
boilers,  house  furnaces,  etc.,  it  is  very 
important  that  the  tendencies  of 
these  currents  should  be  studied, 
and  their  maintenance  and  regularity 
carefully  provided  for.  To  such  cur- 
rents we  owe  the  draught  of  chimneys, 
the  ventilation  of  buildings,  the  trade, 
and  other  winds,  many  great  ocean 
currents,  etc. 

Radiation. — By  this  term  we  indi- 
cate the  transfer  of  heat,  by  motions 
of  the  nature  of  undulations,  or  vibrations,  in  a  certain 
mobile  fluid,  pervading  all  space,  called  the  luminiferous 
aether.  This  impalpable  fluid  or  gas  is  incapable  of  any 
direct  physical  test,  but  is  believed  (for  the  very  strongest 
indirect  reasons)  to  exist,  and  to  be  not  only  the  vehicle 
of  heat,  but  that  also  of  light,  whence  its  name  lumi- 
niferous, or  "light  bearing."  A  hot  and  cold  body 
placed  at  a  distance  in  a  vacuum,  will  rapidly  become 
equalized  in  temperature ;  the  one  gaining,  the  other 
losing  heat.  We  suppose,  in  this  case,  that  the  motions 
of  the  hot  body  have  communicated  vibrations  to  the 
aether,  which  this  has  in  turn  conveyed  to  the  colder. 
Heat  propagated  by  this  means  is  reflected,  refracted, 
absorbed,  polarized,  etc.,  exactly  as  is  light,  and  may,  in 
fact,  be  regarded  simply  as  slowly  moving  (in  the  sense 
of  vibrating)  light.  This,  however,  will  be  more  fully 
discussed,  page  111. 

Radiant  heat  is  best  reflected  by  planished  surfaces  of 
metal,  and  best  absorbed  by  dull,  rough  surfaces,  such  as 
lampblack.  It  is  also  absorbed  in  very  different  degrees, 


LIGHT.  37 

by  gases  and  vapors,  and  by  certain  solids  and  liquids. 
This  absorption  varies,  however,  with  the  character  of 
the  radiant  heat,  as  regards  its  intensity,  heat  from  hot 
iron  at  500°  passing  where  that  from  water  at  200°  would 
not. 

Rock  salt  is  the  most  "  diathermanous"  solid  known,  and 
offers  equally  little  resistance  to  heat  of  all  intensities. 
It  is  by  radiation  that  the  sun's  heat  reaches  us,  or  that 
of  a  fire,  before  which  we  stand,  etc. 


LIGHT. 

By  the  word  Light  we  indicate  the  cause  of  that  sen- 
sation, affecting  the  eye,  when  it  is  turned  upon  the  sun, 
stars,  a  burning  body,  or  the  like. 

This  cause,  we  have  every  reason  to  believe,  is  identical 
in  its  nature  with  heat ;  that  is,  we  believe  it  to  be  simply 
a  very  rapid  vibratory  movement  among  the  particles  of 
ordinary  matter,  and  the  luminiferous  aether  already  men- 
tioned, which  pervades  all  space,  and  most  bodies  (and 
which,  though  too  rare  and  fine  to  admit  of  any  direct 
measurement  or  physical  testing)  is  yet  abundantly 
capable  of  producing  those  phenomena  which  we  attribute 
to  its  agency.  In  fact,  the  conclusions  which  these  phe- 
nomena themselves  lead  us  to  draw,  respecting  its  light- 
ness and  mobility,  forbid  us  to  expect  that,  with  the 
rough  means  at  our  disposal,  we  should  be  able  in  any 
direct  way  to  test  or  examine  it. 

The  difference  between  heat  and  light  consists  simply  in 
the  rapidity  of  the  motions  or  vibrations  producing  them. 
If  these  number  between  450  billions  and  780  billions  per 
second,  they  constitute  light :  if  less  than  the  first,  they 
are  heat:  if  more  than  the  last,  they  are  actinism. 
See  page  54. 

Sources  of  Light, — As  might  be  expected  from  our  theory, 
4 


38 


LIGHT. 


Fig.  17. 


all  sources  of  heat  are,  or  may  become,  if  intensified, 
sources  of  light.  Thus  we  have,  1st,  the  Sun.  2nd.  Me- 
chanical action.  E.  g.  Flint  struck  in  a  vacuum,  Perkin's 
iron  wheel  revolving  6000  times  a  minute,  and  touched 
with  a  steel  file,  Fig.  1*L  3rd.  Electricity.  E.  g.  Sparks, 

lightning,  aurora,  elec- 
tric light,  glowing 
wire,  etc.  4th.  In- 
tense chemical  action. 
E.  g.  Combination  of 
iron  and  sulphur,  phos- 
phorus and  iodine, 
ordinary  combustion, 
etc.  5th.  Phosphores- 
cence. E.  g.  Glow- 
worms, fire-flies,  etc. 
In  all  these  cases  the 
11  light  vibrations  "  are 
developed  exactly  as  those  of  heat — by  the  same  actions. 

Propagation  of  Light.  —  Light  emanates  from  all 
luminous  bodies  in  straight  lines,  radiating  from  every 
luminous  point.  It  passes  without  loss  or  change  through 
free  space,  but  is  variously  acted  upon,  and  changed  in 
its  direction  and  character  when  traversing  different 
bodies.  These  changes  we  shall  study  in  their  order 
presently. 

The  Velocity  of  Light  in  free  space  is  190,000  miles 
per  second.  This  Roemer  proved  by  observation  of  the 
eclipses  of  Jupiter's  first  satellite,  in  1675,  and  Foucault 
demonstrated  experimentally  with  a 
very  ingenious  apparatus,  by  which 
he  was  able  to  prove  that  the  velocity 
of  light  was  less  in  water  and  dense 
media,  than  in  air  and  other  rare 
ones.  Since  light  is  projected  in 


Fig.  18. 


LIGHT.  39 

straight  lines,  an  opaque  body,  placed  before  a  source  of 
light,  will  cut  off  its  rays  from  a  certain  space.  This 
space,  so  deprived  of  light,  we  call  the  shadow.  Thus,  A, 
Fig.  18,  being  a  source  of  light,  and  B  C  an  opaque  body,  the 
indefinite  space,  B  C  E  D,  is 
its  shadow.  If  the  source 
of  light  is  a  point,  or  at  a 
vast  distance  from  B  C,  this 
shadow  will  be  definitely 
bounded  by  B  D  and  C  E; 
but  if  the  source  of  light  con- 
sists of  many  points,  or  an 
extended  surface,  A  B,  Fig.  19,  then  there  will  be  a  full 
shadow,  C  D  E  F,  where  no  light  enters,  and  around  this 
as  penumbra,  or  gradually  decreasing  shade,  G  C  E,  and 
F  D  H,  from  which  is  excluded  the  light  of  some 
only,  among  the  luminous  points  in  A  B. 

Interference. 

Though,  as  a  general  rule,  rays  of  light,  like  sounds, 
may  cross  each  other  in  all  directions,  without  any  inter- 
ference or  mutual  disturbance,  yet  in  certain  cases  inter- 
ferences may  occur.  Thus,  if  two  rays  are  brought 
together  in  such  a  way  that  the  rising  phase  in  the 
vibrations  or  waves  of  one,  corresponds  with  the  sinking 
phase  of  the  other,  their  opposite  motions  will  be  mutually 
destructive ;  the  light  motion  will  cease,  and  the  light  will 
disappear.  Two  rays  of  light  may  thus  unite  to  produce 
darkness.  If,  however,  the  two  waves  of  light  coincide 
in  phase  of  motion,  a  double  brightness  is  the  result. 
This  action  has  the  most  exact  parallel  in  sound,  and  in 
undulations  of  liquids,  etc.  Thus,  an  opening  like  figure 
20  being  made  between  two  rooms,  a  sound  produced  in 
one  of  them  will  not  be  heard  in  the  other,  unless  one  of 
the  two  openings,  cd,  is  closed  ;  because  the  sound  waves 


40 


LIGHT. 


coming  through  the  two  passages,  and  meeting  in  different 
phases,  effect  a  mutual  destruction.  We  shall  have  fre- 
quent cause  to  refer  to  this  subject  of  interference. 

Fig.  20. 


But  at  present  we  shall  confine  ourselves  to  one  case. 
Two  adjacent  cones  of  light,  proceeding,  for  example, 
from  two  pinholes  near  together  in  a  card,  produce  on  a 
screen,  at  a  short  distance,  a  series  of  dark  and  light 
bands  in  homogeneous  and  colored  fringes  in  mixed  or 
white  light. 

Diffraction.  —  By  this  term  we  indicate  the  effect  pro- 
duced on  light,  in  passing  across  the  edge  of  an  opaque 
body.  In  this  case  a  new  system  of  undulations  is 
developed  in  the  ether,  having  the  solid  edge  as  their 
centre.  These,  by  their  interference  with  the  original 
rays,  produce  fringes  of  light  and  darkness  (or  color  with 
mixed  light)  within  and  without  the  geometric  shadow 
of  the  solid  edge.  Wires,  gratings,  etc.,  act  in  the  same 
way. 


LIGHT. 


41 


Fig.  21. 


M 


Reflection.  — When  a  ray  of  light  falls  upon  a  polished 
surface,  it  is  thrown  off  again  at  an  angle  the  same  as 
that  of  its  incidence.  This  may 
be  well  shown  as  follows :  The 
mirror,  M,  being  so  adjusted 
that  a  ray  of  light  from  any 
source  is  thrown  down  through 
a  diaphragm,  N,  upon  a  pol- 
ished horizontal  surface,  n; 
this  ray  will  be  reflected  up- 
ward, and  will  fall  upon  the 
little  movable  screen,  P,  when 
this  is  so  adjusted,  as  to  make 
the  angle  A  n  P  equal  to  the 
angle  A  n  N.  From  this  it 
follows,  that  parallel  rays,  fall- 
ing on  a  plane  polished  surface, 
are  reflected  in  parallel  lines 
(see  Fig.  22),  and  that  diverging  rays  are  reflected  with 


Fig.  22. 


Fig.  23. 


the  same  divergence^  as  before,  the  only  change  being, 
that  they  now  seem  to  diverge  from  a  point  as  far  below 
the  reflecting  surface  as  their  actual  source  is  above  it. 
(See  Fig.  23). 

If,  therefore,  we  are  not  aware  of  the  reflecting  surface, 
we  may  suppose  the  light  to  come,  not  from  its  true 
source,  but  from  this  supposed  or  equivalent  source, 
behind  the  reflecting  surface. 

This  principle  has  been  applied  in  Dr.  Pepper's  theatri- 
4* 


42 


LIGHT. 


cal  arrangement  for  "the  ghost."    A  large  sheet  of  plate 
glass,  A  B,  without  silvering,  is  fixed  near  the  front  of 


the  stage.  The  "  ghost,"  brightly  illuminated  by  a  lime- 
light, is  placed  at  C  D,  and  the  rays  of  light  passing  from 
this  figure  through  the  trap  door,  C  B,  and  reflected  from 
A  B,  enter  the  eyes  of  the  audience  at  O,  just  as  if  they 
came  from  a  similar  figure  standing  on  the  stage  at  E  T. 
The  mirror  may  also  be  placed  at  an  angle  across  the 
stage,  and  the  "  ghost "  reflected  from  behind  one  of  the 
wings. 

If  the  reflecting  surface  is  curved,  parallel  rays  falling 
upon  it  at  different  places,  will  make  with  it  different 
angles,  and,  hence,  will  be  reflected  in  dif- 
ferent directions. 

If  the  reflecting  surface  is  of  parabolic 
form,  then  parallel  rays  falling  on  it  will 
be  reflected  to  one  point,  called  its  focus, 
and  reciprocally  a  source  of  light  being 
placed  in  this  focus,  its  rays  are  all 
thrown  out  in  parallel  lines. 

The  reflecting  power  of  different  bodies 
is  very  various,  and  changes  with  the  angle  of  the  inci- 
dent light.  Transparent  bodies,  such  as  glass,  at  certain 
angles,  allow  part  of  the  light  to  be  transmitted,  and  part 


Fig.  25. 


LIGHT. 


43 


to  be  reflected.  This  last  increases  with  the  obliquity  un- 
til a  certain  point  is  reached,  called  the  angle  of  total  re- 
flection, when  all  is  reflected,  and  the  body  is,  as  it  were, 
absolutely  opaque. 

The  following  table  illustrates  the  relative  reflecting 
power  of  a  few  substances  at  different  angles. 

The  incident  light  making  angles  with  the  surface  of 


5° 

15° 

30° 

60°  to  90° 

Water  

72 

21 

6.5 

1.8 

Glass  (1st  surface)  
Black  Marble,  polished 
Mercury  as  on  Mirrors 

64 
60 
70 

30 
15.6 
16.6 

11.2 
5.1 
5.1 

2.5 
2.3 

60. 

Unpolished  surfaces,  by  reason  of  their  minute,  invisi- 
ble, but  countless  irregularities,  reflect  the  light  they 
receive  in  all  directions ;  or,  in  other  words,  disperse  it, 
thus  becoming,  in  this  respect,  similar  to  luminous  bodies. 
Part  of  the  light  received  is  of  course,  however,  absorbed, 
even  if  the  body  is  white ;  and  if  it  is  colored,  it  must 
absorb  all  those  colors  which  it  does  not  give  back.  Thus, 
a  red  body  absorbs  all  the  colors  but  red,  a  green  one  all 
but  green. 

When  the  reflecting  surface  is  corrugated  very  finely, 
as  is  the  case  with  mother  of  pearl,  fine  rulings  on  glass, 
etc.,  the  reflected  rays  from  adjacent  ridges  (being  very 
little  separated),  will  interfere  and  produce  (in  mixed  or 
white  light),  colored  fringes,  or,  as  it  is  called,  "iri- 
descence."  All  visible,  non-luminous  objects  also  reflect 
light,  but  from  extreme  irregularity  of  surface,  presenting 
all  angles  to  the  incident  ray,  they  throw  it  off  in  all 
directions,  like  luminous  bodies. 

Reflection  will  not  only  take  place  at  the  surface  of  a 
dense  medium,  but  also  of  a  rare  one.  Thus,  an  object 
may  be  seen  reflected  from  below  a  surface  of  water, 
where  we  may  regard  the  air  as  the  reflecting  surface 


44 


LIGHT. 


(see  Fig.  26),  or  from  the  rear  surface  of  a  plate  of  glass, 
where  the  same  is  true.     So,  also,  a  ray  of  light,  passing 

Fig.  26. 


Fig.  27. 


out  with  a  vein  of  flowing  water,  will  be  reflected  back 
and  forth  from  the  interior  surface  of  the  water,  thus  fol- 
lowing the  stream  and  illuminating  it,  and  seeming  to 
bubble  up  where  the  stream  breaks. 

By  an  extensive  application  of  this  principle,  the  beau- 
tiful experiment  of  the  illuminated  fountain. is  arranged, 
the  jets  being  lit  up  by  two  powerful  lime  or  electric  lan- 
terns, one  immediately  below,  and  the  other  directly 
above  them. 

If  light  falls  obliquely  on  a  very  thin  plate,  as  in  a  soap 
bubble,  film  of  oil  on  water,  etc.,  the  rays 
reflected  from  the  first  and  second  sur- 
faces, may  interfere,  being  very  little 
apart  (see  Fig.  2f),  and  thus  produce, 
with  mixed  or  white  light,  colors  depend- 
ent upon  the  thickness  of  the  film,  as  will 
be  explained  further  on.  The  rays  which  pass  through 

will  also  suffer  interference 
from  those  twice  reflected 
within  the  plate,  so  giving  us 
the  same  effect  by  transmit- 
ted, as  by  reflected  light. 
The  film  may  be  of  a  rare 
substance,  as  air  inclosed  be- 


Fig.  28. 


LIGHT. 


45 


Fig.  29. 
A 


tween  two  plates  of  glass.  If  this  air  film  varies  in 
thickness  regularly  around  a  centre,  as  when  it  is  pro- 
duced by  placing  a  lens  upon  a  plate  of  glass  it  will  de- 
velop, with  white  light,  concentric  rings  of  color.  These 
are  known  as  Newton's  rings.  The  apparatus  for  produc- 
ing them  is  shown  at  Fig.  28. 

Refraction. — A  ray  of  light,  coming  obliquely  upon  the 
surface  of  a  body  more  or  less  dense  than  that  through 
which  it  was  before  passing,  is  bent  from  its  course,  and 
passes  on  in  a  new  direction.  This  bending  is  called 
refraction. 

Where  the  ray  passes  from  a  rare  to  a  dense  body,  it  is 
bent  inward    towards    the   latter;    in 
passing  from  dense  to  rare  this  is  re- 
versed.    In  other  words,  the  path  of    "  \  \ 
the  ray  would  be  the  same  whichever          \^         \  •" 

way  it  went ;  or  if  it  passes  through  a          Q\ \C\ 

dense  or  rare  body  with  parallel  faces,  \ 

it  will  simply  be  displaced,  not  changed 

in  its  direction.     (See  Fig.  29.)     If  the  opposite  sides  of 

the  body  were  not  parallel,  however,  F.    30 

its  direction   would  be  changed  (see 

Fig.  30). 

The  amount  of  this  bending  differs 
with  different  bodies,  and  also  with  the  angles  of  the 
incident  rays.  The  relative  refracting  powers  of  differ- 
ent substances,  are  indicated  by  certain  numbers,  called 
"INDICES  OP  REFRACTION."  These  are  determined  by 
experiment.  See  Table. 

Table  of  Indices  of  Refraction.  —  Solids. 


Chromate  of  Lead...  2.50  to  2.97 

Diamond 2.47  to  2.75 

Phosphorus 2.224 

Glass  of  Antimony.  2.216 
Native  Sulphur 2.115 


Zircon 1.95 

Borate  of  Lead 1.866 

Carbonate  of  Lead..  1.81  to  2.08 

Ruby 1.779 

Felspar 1.764 


46 


LIGHT. 


Tourmaline  1.668 

Spermaceti 

1  503 

Topaz,  colorless....  1.610 
Beryl  1  598 

Crown  Glass   

..   1.500 
1  509 

Sulphate  of  Potash 

Emerald                      1  585 

Sulphate  of  Iron 

1  494 

Flint-glass  1  57  to  1  58 

Tallow,  Wax... 

.  1  492 

Quartz     ....         .  .  1  547 

Sulphate  of  Magnesia 

1  488 

Rock  Salt  1.545 

..   1.654 

Rosin   1543 

Obsidian  

..  1.488 

Sugar                          1  535 

Gum  Arabic    

..   1  476 

Phosphoric  Acid  ...  1.544 
Sulphate  of  Copper  1.53  to  1.55 
Citric  Acid                 1  527 

Borax  

..  1  475 

..  1.465 

Fluor-spar  

..   1.436 
..  1.310 

Nitre                           1  514 

Liquids. 
Bisulphide  of  Carbon  1.678      Nifrin  A^id    1-48  

..  1.410 

Oil  of  Cassia  1.631 

Sol.  Caustic  Potash,  1.41 

..  1.405 
1  410 

Oil  of  Bitter  Almonds  603 

Canada  Balsam  528 

Sol    of  Common  Snlt 

1  575 

"        Linseed  485 

Alcohol    rectified 

1  372 

"       Naphtha,  rapeseed     .475 
"       Olive  1.470 

Sulphuric  Ether  

..  1.358 
1  356 

Sol    of  Alum 

4<        Turpentine               1  470 

Blood 

1  354 

"       Almond  469 

Albumen,  White  of  Egg.. 
Distilled  Vinegar  

..  1.351 
..  1.372 

"        Lavender  467 

Sulphuric  Acid   1-7              1  429 

Water  

..  1.336 

.000449 
.000340 
.000449 
.000834 
.000678 
.000443 
.001095 
.900153 
.000150 

Gas 
Air  000294 

es. 

Hydrochloric  Acid  
Carbonic  Oxide 

Oxygen                   ....          .000272 

Hydrogen  000138 

Carbonic  Acid  

Nitrogen  000300 

Cyanogen  

Chlorine                               000772 

Olefiant  Gas 

Nitrous  Oxide                      000503 

Marsh  Gas 

Nitric  Oxide  000303 

Hydrochloric  Ether  
Sulphuric  Ether  

Ammonia             .        .      1  000385 

Sulphuretted  Hydrogen  1.000644 

Sulphide  of  Carbon  

LIGHT. 


47 


Fig.  31. 


Fig.  32. 


To  obtain  the  actual  refraction  for  a  given  ray  by  a 
given  substance,  we  have  this 
rule.  The  sine  of  the  angle  of 
the  ray  after  refraction,  equals 
the  sine  of  the  angle  of  the  in- 
cident ray  divided  by  the  refrac- 
tive index  of  the  body  in  ques- 
tion. Thus,  suppose  an  inci- 
dent ray,  A  B,  whose  sine  is 
C  D,  then  the  sine,  G  0,  of  the  angle,  E  B  G,  which  the 
ray  makes  after  entering  the  dense  body,  X  Y,  is  equal 
to  C  D  divided  by  the  index  of  refraction  of  X  Y. 

Thus,  if  X  Y  is  flint-glass,  E  G  =  C  D,  1.6  being  the 
index  of  refraction  of  this  substance.  We  have  already 
seen,  that  if  the  opposite  surfaces  of  a  refracting  medium 
are  not  parallel,  the  direction  of  a  ray 
passing  through  will  be  changed. 
(Fig.  29.)  It  is  moreover  evident 
that  if  these  surfaces,  one  or  both, 
are  curved,  the  rays  falling  upon 

them  will  be  more  or  less  converged  towards  a  point,  or 
diverged  and  scattered,  according 
as  the  curve  or  curves  are  convex 
or  concave.  See  figures  32,  33 
and  34.  If  now  the  convex  curves 
should  be  elliptical,  the  following  re- 
sults would  be  accurately  attained. 

Parallel  rays  falling  upon  the  lens 

would  all  be  converged  and  collected  at  a  certain  point 
O,  Fig.  35,  which  is  called  Fig.  34. 

the  "  FOCUS."  The  distance 
C  O  is  called  the  "FOCAL 
DISTANCE."  This  is  fixed 
for  the  same  lens,  but  dif- 
fers with  the  material  and 


Fig.  33. 


48 


LIGHT. 


Fig.  35. 


curvature  of  different  lenses.  We  can  roughly  determine 
this  for  any  lens,  by  holding  it 
up  at  some  distance  from  a, 
window,  and  finding  how  far 
from  it  a  sheet  of  paper  must 
be  held,  to  receive  a  sharp 
image  of  the  same.  This  will 
be  the  focal  distance. 

If  instead  of  parallel  we  have 
divergent    rays     coming    upon 

the  lens,  say  from  C.  outside  of  the  focus  0',  they  can- 
not, of  course,  be  collected 
at  so  near  a  point  as  0, 
but  yet  will  be  centered 
at  some  more  distant  one 
C'.  If  C  comes  nearer 
to  O',  C'  will  be  further 
off  from  0.  These  points 

C  and  C'  are  called  "  conjugate  foci,"  and  of  course  admit 
of  an  infinite  variety  of  values  in  the  same  lens,  though 
always  having  a  fixed  inverse  relation  to  each  other.  If 
C  corresponded  with  O',  the  rays  would  emerge  from 
the  lens  parallel,  and  thus  have  no  focus.  If  C  were 
inside  of  0',  the  emerging  rays  would  diverge.  A  con- 
cave lens  reverses  all  the  actions  of  a  convex  one. 
Formation  of  Images  by  Lenses,  —  Again,  if  rays  from 

.  37. 


points  not  in  the  line  C  C',  such  as  P  and  0  come  upon 
the  lens  A  B,  they  will  be  focussed  at  certain  points  P' 


LIGHT. 


49 


and  0',  bearing  the  same  relation  to  P  and  0  that  C' 
does  to  C.  We  shall  thus  have  an  image  formed  at  O' 
P'  of  luminous  or  illuminated  object,  differing  in  size,  as 
the  conjugate  foci  differ  in  distance  from  the  lens.  So 
that  a  small  object,  brought  near  to  the  lens,  will  make  a 
large  image  at  a  distance,  while  a  large  body  at  a  dis- 
tance will  make  a  small  image  close  to  the  lens.  E.  g. 
For  the  first,  the  solar  or  gas  microscope  and  magic 
lantern  ;  for  the  last,  the  camera  obscura.  The  image, 
as  we  see,  will  be  inverted.  This  image  may  be  again 
magnified  by  another  lens  placed  beyond  0'  Pr,  Fig.  37. 

Spherical  Aberration.  —  All  that  we  have  said  would  be 
strictly  true  of  lenses  whose  curves  are  eliptical  or  hyper- 
bolic ;  but  in  practice  such  lenses  cannot  be  constructed; 
their  curves  must  be  spherical.  Now  with  spherical  lenses 
the  rays  passing  through  the  edges  are  more  refracted  than 
those  traversing  the  central  portion,  and  are  therefore  fo- 
cussed  at  a  nearer  point.  Hence,  the  clear  image,  C  D,  made 
by  the  central  rays  would  be  obscured  by  the  scattered  light, 
O  P,  from  the  edges, 

and     likewise     with  Flg' 38> 

the  image  of  the 
border  rays.  With 
a  single  spherical 
lens  we  cannot  ob- 
tain a  perfectly  sharp 
image,  owing  to  this, 
which  is  called  ''spherical  aberration." 

By  the  combination,  however, 
of  two  or  more  lenses  of  different 
curvature,  this  difficulty  is  over- 
come. For  details,  see  Brew- 
ster's  optics.  We  have  the  fol- 
lowing forms  of  lenses  in  common 
use:  A,  Piano  convex;  B,  Piano 
5 


Fi 


50  LIGHT. 

concave ;   C,   Double    convex ;   D,    Double   concave ;  E, 
Meniscus. 

Double  Refraction.  —  When  a  transparent  solid  is  sub- 
jected to  pressure  or  strain  in  one  direction,  it  splits  or  sepa- 
rates an  incident  raj  into  two,  one  of  these  being  refracted 
according  to  the  laws  already  expressed,  the  other  in  a  dif- 
ferent direction  and  degree.  The  first  is  called  the  "  ordi- 
nary ;"  the  second  the  "extraordinary  ray."  Many 
crystalline  and  other  bodies  possess  the  same  properties, 
owing  to  the  molecular  strain  generated  in  them  by  the 
crystalline  force.  Among  these  the  most  remarkable  is 
Iceland  Spar,  carbonate  of  lime  crystallized  in  oblique 
rhombohedric  prisms.  These  crystals 
have  two  obtuse  and  six  acute  solid  angles, 
a  line  joining  the  obtuse  angles  is  called 
the  AXIS  of  the  crystal.  In  this  direction 
alone  it  has  no  double  refraction,  any 
plane  parallel  to  this  axis  is  called  a 
"  PRINCIPAL  SECTION,"  as  A  X  B  Y.  In 
every  other  it  separates  the  rays  in  a  most  complete 
manner,  so  that  a  line  seen  through  a  moderate  thickness 
of  this  substance  appears  double.  We  shall  return  to 
this  property  under  the  head  of  "polarized  light." 

Though  Iceland  Spar  alone  possesses  the  property  of 
double  refraction  in  so  great  a  degree  as  to  be  at  once 
evident  to  mere  casual  observation,  a  multitude  of  other 
bodies  have  the  same  power  in  much  lower  degree. 
Thus  quartz  may  be  made  to  show  a  double  image,  if 
formed  into  a  prism,  as  will  be  presently  explained.  So 
also  with  glass  under  pressure ;  by  combining  many 
prisms,  a  double  image  may  be  obtained.  Except,  in- 
deed, for  the  mechanical  difficulties,  similar  treatment 
would  develop  like  results  in  nearly  all  crystalline  bodies, 
except  those  of  the  "  monometric"  system,  i.  e.,  cubes, 
octohedrons,  and  their  derivatives,  in  most  animal  and 


LIGHT.  51 

vegetable  fibres,  shells,  scales,  granules,  etc.,  and  even  in 
some  liquids.  By  certain  effects,  however,  resulting  from 
this  double  refraction,  hereafter  to  be  described,  its  exist- 
ence in  all  these  bodies  is  easily,  though  indirectly  de- 
monstrated. To  develop  double  refraction  strongly  in 
quartz,  we  cut  two  prisms  from  a  crystal  in  such  a  way 
that  in  A  B  C  E  D  the  axis  of  the 
crystal  is  in  the  direction  A  B,  and 
in  B  C  F  G  D  E  parallel  to  G  F, 
and  cement  their  oblique  faces 
together.  A  ray  then  entering  the 
surface  A  D  E  I  at  right  angles, 
suffers  no  change  until  it  reaches 
the  surface  D  E  C  B  at  X,  when 
it  is  separated  by  double  refraction,  aided  by  the  obliquity 
of  the  prism,  into  two  rays,  X  P  and  X  Q.  This  appa- 
ratus is  called  the  Prism  of  Rochon.  A  similar  prism  may 
be  made  of  Iceland  Spar,  or  we  may  use  simply  a  single 
prism  of  that  substance,  correcting  its  chromatic  aberration, 
by  a  compensating  prism  of  glass.  Such  a  "  double  image 
prism,"  as  it  is  called,  will  give  an  enormous  separation 
to  the  two  rays,  or  images. 
See  APPENDIX,  page  294  To  Fig.  42. 

show  the  double  image  with 
compressed  glass,  a  system 
of  prisms  is  arranged,  as  in 
the  drawing,  so  that  A  B  C  D 
project  and  suffer  compression  from  plates  of  metal  forced 
against  their  ends.  The  intermediate  prisms,  R  M  N, 
etc.,  not  pressed,  serve  to  correct  in  the  ray  passed  from 
R  to  T,  all  deviation,  dispersion,  etc.,  except  that  double 
refraction  produced  by  the  pressure. 

Composition  of  White  Light— We  have  heretofore  spoken 
of  light  as  if  it  were  all  of  one  kind ;  a  simple  motion  of 
a  definite  sort.  Every  thing  we  have  said  would  indeed 


52 


LIGHT. 


Fig.  43. 


be  strictly  true,  say  of  pure  yellow  light,  such  as  is  pro- 
duced by  burning  alcohol  and  salt;  but  would  require 
certain  limitations  if  applied  to  white  light,  which  is  what 
we  generally  understand  by  the  unlimited  noun  "light." 
This  light  is  far  from  being  simple ;  and  we  will  now  pro- 
ceed to  study  its  nature. 

If  a  ray  of  light,  passing  through 
a  narrow  opening  or  slit,  is  al- 
lowed to  fall  upon  a  refracting 
prism  whose  axis  is  parallel  to 
this  opening,  it  will  of  course  be 
refracted  or  bent  from  its  course ; 
but  instead  of  producing  a  single 

line  of  light  upon  a  screen  placed  in  its  path,  it  will 
develope  a  broad  band,  in  which  all  the  colors  of  the 
rainbow  will  be  found  beautifully  blended.  It  would 
thus  appear  that,  in  the  ray  of  white  light  were  all  these 
colors. 
This  decomposition  of  white  light  may  be  strikingly  shown 

Fig.  44. 


LIGHT. 


53 


as  follows.  (See  Fg.  44.)  We  place  Fig.  45. 

as  an  object,  in  an  ordinary  magic- 
lantern,  B,  arranged  for  the  lime- 
light, a  plate  of  brass  having  an 
opening  in  it  i  of  an  inch  wide, 
shaped  like  a  rainbow,  with  3 
inches  span.  This  being  properly 
"focussed  "  on  a  screen,  say  at  a 
distance  of  50  feet,  the  lantern 
should  be  tilted  up,  as  shown  in 
the  drawing,  and  a  prism  held  as 
indicated  by  the  figure,  in  front  of 
its  object  lens.  The  arch  of  light 
will  then  be  depressed  by  refrac- 
tion to  the  proper  place  on  the 
screen,  and  broken  by  dispersion 
into  all  the  prismatic  or  rainbow 

hues.  The  prism  for  this  experiment  should  be  made  by 
grinding  a  glass  bottle  into  the  shape  shown,  figure  45, 
cementing  plates  of  glass  on  the  open  sides  with  the 
mixture  of  molasses  and  glue  used  by  printers  to  make  their 
"  inking-rollers,"  and  filling  it  with  bisulphide  of  carbon. 

We  know  on  general  mathematical  principles,  that  the 
more  rapid  the  vibrations  in  a  ray,  the  more  it  ought  to 
be  refracted ;  and  we  therefore  conclude  that  white  light 
consists  of  not  one  only,  but  many  'kinds  of  motions ;  the 
slowest  of  which,  separated  from  the  others  as  at  R,  is 
recognized  as  red  light,  while  the  most  rapid  is  seen  as 
violet  at  V;  and  all  others  arrange  themselves  in  gradual 
progression  as  indicated  in  the  plate  facing  page  123. 

Nor  does  our  experiment  stop  here.  By  the  use  of  deli- 
cate thermometric  apparatus,  (see  page  121)  we  find  that  be- 
low R,  Fig.  43,  intense  heat  is  present,  gradually  fading  off 
as  we  descend ;  while  a  sensitive  photographic  plate  or 
fluoresent  screen  will  inform  us,  that  above  Y,  (for  a  distance 
5« 


54  LIGHT. 

more  than  five  times  as  great  as  R  V,  if  an  electric  light 
and  lenses  and  prisms  of  quartz  are  used,)  there  is  spread 
an  influence  which,  though  invisible,  acts  most  powerfully 
in  effecting  photo-chemical  decomposition,  and  may  even 
become  perceptible  to  the  eye  through  the  influence  of 
fluoresent  action,  this  we  call  ACTINISM. 

The  variegated  band  or  ribbon  of  light  thus  obtained  is 
called  a  "  SPECTRUM."  If  sunlight  is  used  in  this  experi- 
ment, and  the  spectrum,  in  place  of  being  projected  upon 
a  screen,  is  examined  through  a  telescope  into  which  it  is 
thrown,  countless  fine  black  lines  will  be  seen  crossing 
the  band,  which  from  their  discoverer  are  called  FRAUN- 
HOFFER'S  LINES.  Passing  over  their  cause,  to  be  hereafter 
discussed,  ,we  at  present  notice  only  that  they  are  abso- 
lutely fixed  with  reference  to  the  colors  of  the  spectrum, 
and  their  relative  places  in  its  length  ;  and  being  sharp 
and  well  defined,  are  of  the  greatest  use  with  regard  to 
all  purposes  of  measurement.  (See  plate.)  The  most 
prominent  of  these  are  marked  upon  the  plate,  and  desig- 
nated by  the  letters  which  have  always  been  «used  to 
describe  them.  If  by  another  inverted  prism  or  lens,  or 
otherwise,  these  colors  are  united,  they  produce  white 
-light  again.  It  is  customary  to  speak  of  the  colors  con- 
tained in  white  light  and  constituting  the  spectrum,  as  seven 
in  number:  Red,  Orange,  Yellow,  Green,  Blue,  Indigo, 
and  Violet;  or  as  3  primary  colors:  Red,  Yellow,  and 
Blue,  with  the  various  tints  which  would  be  developed 
by  their  combination ;  as  Green  composed  of  Yellow  and 
Blue,  Violet  of  Red  and  Blue,  and  Orange  of  Red  and 
Yellow.  In  this  case,  regarding  the  spectrum  as  being 
made  of  three  graduated  spectra,  one  of  red,  one  of  yel- 
low, and  one  of  blue  light,  which,  variously  overlaying 
each  other,  produce  all  the  blended  tints. 

Complementary  colors  are  such  a  pair  as  would,  united, 
make  white.  One  of  these  at  least  must  therefore  be  a 


LIGHT. 


55 


compound  color.  Thus,  red  and  green,  yellow  and  violet, 
blue  and  orange,  are  complementary  colors.  We  ought, 
however,  to  remember  that  the  above  ideas  are  adopted 
merely  for  convenience ;  and  that  every  tint  is  as  truly  a 
distinct  thing,  as  each  note  in  a  musical  scale.  That  each 
tint  of  color  represents  simply  so  many  vibrations  per 
second. 

Lengths  of  Undulations  and  Numbers  per  Second. 


Lengths  in  parts 
of  an  inch. 

Number  in 
an  inch. 

Number  per  second. 

"Line  B 

.00002708 

36.918 

'    451  000  000  000  000 

Line  C    

.00002583 

38.719 

473,000  000  000  000 

Middle  Red  

.00002441 

40.949 

500,000,000  000  000 

Line  D  

.00002319 

43.123 

527,000,000,000  000 

Middle  Orange... 
"       Yellow... 
Line  E 

.00002295 
.00002172 
.00002072 

43.567 
46.034 

48.286 

532,000,000,000,000 
562,000,000,000,000 
590  000  000  000  000 

Middle  green  
Line  F  

.00002016 
.00001909 

49.609 
52.479 

606,000,000,000,000 
641,000,000  000  000 

Middle  blue  
"       indigo.... 
Line  G 

.00001870 
.00001768 
.00001689 

53.472 
56.569 
59  205 

653,000,000,000,000 
691,000,000,000,000 
723  000  000  000  000 

Middle  violet  
Line  H  

.00001665 
.00001547 

60.044 
64  631 

733,000,000,000,000 
789  000  000  000  000 

Spectrum  Analysis. 

We  find  that  certain  bodies,  when  vaporized  in  a  flame, 
communicate  to  it  definite  colors;  as  sodium,  yellow;  stron- 
tium, red ;  barium,  green,  etc. ;  and  we  naturally  conclude 
that  the  particles  of  these  bodies  are  capable  of  vibrating 
at  certain  rates,  corresponding  to  these  colors,  and  at  no 
others.  This  supposition  is  most  completely  confirmed. 
If  we  look  at  the  spectrum  produced  by  a  flame  otherwise 
non-luminous  (as  of  alcohol,  a  Bunsen  burner,  etc.),  in 
which  sodium  is  introduced,  we  shall  see,  in  place  of  the 
rich  band  of  various  colors,  simply  a  single  sharply  defined 
yellow  line  (see  plate  facing  page  123,  Na.)  ;  showing  that 


56  LIGHT. 

all  the  vibrations  here  present,  are  of  exactly  one  velocity. 
Strontium,  in  like  conditions  giving  a  purplish  red  light 
will  show  us  some  red  lines  and  one  bright  blue  (see  plate 
facing  123,  Sr. ;)  so  with  other  bodies,  especially  the  metals. 
The  amount  of  the  material  needed  to  produce  these 
effects,  is  extremely  small ;  and  we  at  once  see  that  we 
have  here  a  most  useful  and  wonderful  means  of  chemical 
analysis  for  some  bodies. 

We  provide  ourselves  with  a  SPECTROSCOPE,  which  con- 
sists essentially  of  a  narrow  slit  or  opening,  a  prism,  and 
telescope  to  examine  the  spectrum,  and  a  Bunsen  burner 
with  a  stand  supporting  a  loop  of  platinum  wire.  We 
then  fasten  the  substance  to  be  examined  in  the  platinum 
wire,  support  it  in  the  flame  of  the  burner,  and  examine 
the  spectrum  of  this  flame  with  the  spectroscope.  The 
lines  we  then  see,  tell  us  at  once  of  the  presence  of  certain 
substances,  and  the  lines  we  miss,  of  the  absence  of  others ; 
due  allowance  being  made  for  certain  effects  of  combina- 
tion, which  we  have  not  here  space  to  discuss. 

Absorption  Bands 

To  produce  the  bright  lines  above  mentioned,  the  heated 
body  must  be  in  the  state  of  vapor  ;  a  highly  heated  solid, 
gives  out  rays  of  all  velocities,  and  hence  produces  a  con- 
tinuous spectrum.  But  if  this  mixed  or  white  light — this 
harmony  of  various  notes  —  passes  through  such  a  vapor, 
capable  of  but  one  or  two  rates  of  motion,  the  rays  of 
the  white  light  which  correspond  with  these,  communicate 
all  their  motion  to  the  vapor  particles,  and  so  lose  the 
power  of  further  onward  propagation.  Thus,  a  ray  of 
white  light,  which  has  traversed  such  a  vapor,  will  have 
lost  just  those  motions  which  the  vapor  itself  would  pro- 
duce ;  and  if  resolved  into  a  spectrum,  will  show  blank 
spaces,  that  is  in  fact  dark  lines,  where  these  rays  should 
have  been. 


LIGHT.  57 

This  may  be  proved  experimentally  in  a  most  direct 
and  striking  manner  (see  Tyndall,  on  Heat,  p.  427) ;  and 
furnishes  us  at  once  with  a  means  of  accounting  for  the 
Frauenhofer  lines.  (This  was  first  pointed  out  by  Bunsen 
and  Kirchoff).  An.  de  Chem.  et  Phy.  T.  68.  p.  5. 

The  sun's  light  proceeds  from  within  his  atmosphere. 
This  atmosphere  consists  of  incandescent  vapors.  Each 
substance  in  this  vapor  abstracts  certain  vibrations,  and 
produces  certain  blank  spaces,  or  dark  lines.,  in  the  spec- 
trum. By  comparing  these  dark  lines  with  the  bright 
lines  of  vaporized  bodies,  we  may  determine  what  ma- 
terials are  found  in  the  solar  atmosphere ;  and  thus  reach 
the  grand  idea  of  analyzing  an  orb  95  millions  of  miles 
distant.  We  conclude,  in  fact,  that  the  principal  solar 
lines  indicate,  as  above,  certain  bodies  in  his  atmosphere, 
as  follows : 

B  indicates     Potassium. 

C  "  Hydrogen. 

D  «  Sodium. 

E  "  Iron. 

b  "  Iron  and  Magnesium. 

F  "  Strontium  (?),  Iron,  and  Hydrogen. 

G  »  Iron. 

H  "  Calcium. 

We  also  recognize  chromium,  nickel,  and  possibly,  zinc, 
cobalt,  and  manganese  ;  but  find  no  indications  of  lithium, 
copper,  or  silver. 

This  process  has  been  also  applied  to  many  fixed  stars 
and  nebulae,  and  has  shown  us  that  some  of  these  last 
(even  those  which  have  been  resolved ;  as  the  dumb-bell, 
that  in  sword-handle  of  Orion,  etc.,)  are  not  star  clusters, 
but  gaseous  bodies  ;  since  they  give  three  bright  lines,  and 
not  continuous  spectra.  (See  Journal  of  the  Franklin 
Institute,  Vol.  49,  p.  1865). 

Vaporized  bodies,  however,  do  not  alone  possess  this 
power  of  absorption.  Many,  or  all  gases,  at  ordinary 


58 


LIGHT 


temperatures,  liquids,  and  solids,  act  in  a  similar  manner ; 
and  the  study  of  these  absorption  bands  has  opened  a 
new  field  to  chemical  research.  (See  Journal  of  Chemical 
Society,  1864,  Vol.  2.,  pp.  59,  304.)  Reference  will  be  made 
from  time  to  time  to  these  matters,  under  the  heads  of 
the  various  substances  which  have  special  relation  thereto. 
Fluorescence.  —  When  light  vibrations  of  very  great 
rapidity,  such  as  belong  to  actinism  rather  than  to  light, 
fall  upon  certain  bodies,  they  cause  them  to  vibrate,  but 
with  less  velocity,  so  that  visible  rays  are  thrown  off  from 
them  in  place  of  the  actinic  ones  which  they  have  received. 
Thus,  if  the  spectrum,  made  with  lenses  and  prisms  of 
quartz  from  the  electric  light,  is  caused  to  fall  on  a  sheet 
of  paper  coated  with  a  solution  of  sulphate  of  quinine  in 
water  containing  tartaric  acid,  a  long  band,  above  the 
part  generally  luminous,  will  be  seen  to  glow  with  pearly 
blue  light.  This  light  contains  dark  bands  analagous  to 
the  Frauenhofer  lines.  A  great  number  of  substances 
possess  this  power ;  canary-colored  glass,  extract  of  sun- 
flower, of  horse-chestnut  bark,  of  chlorophyl,  of  turmeric, 
nitrate  of  uranium,  and  the  natural  phosphate  of  the 
same,  as  also  a  phosphate  prepared  in  a  peculiar  manner 
to  resemble  the  native  phosphate.  But  none  act  in  so 
striking  a  manner  as  quinine  and 
canary  glass. 

The  light  best  fitted  to  develop 
these  effects,  is  that  obtained  by  the 
electric  discharge  in  a  vacuum,  and 
no  experiment  in  physics  can  exceed 
in  beauty  that  which  is  seen  when 
the  discharge  of  a  Ruhmkorff  coil  is 
caused  to  flow  from  the  tinfoil  lining 
of  a  canary  goblet,  over  its  edge  to 
the  pump  plate,  under  an  exhausted 
bell-jar.  We  then  have  a  goblet  of  lu- 


Fig.  46. 


LIGHT. 


59 


minous  emerald,  filled  with  fire,  from  which  pink,  purple,  and 
blue  streams  pour  over  on  every  side,  and  drip  at  every  part. 
A  very  beautiful  effect  is  also  produced  by  passing  the 
discharge   through    an    exhausted  Fig.  47. 

electric  egg  of  this  same  glass, 
and  figures,  painted  on  a  screen 
with  quinine,  entirely  invisible  by 
-  ordinary  light,  become  luminous 
in  the  dark  by  the  light  of  the 
"  aurora  tube  "  (Fig.  79). 

Phosphorescence, 

When  these  reverberations  or 
secondary  vibrations  of  light  are 
very  persistent,  and  last  for 
some  moments  after  the  cause  of 
them  has  ceased  to  act  (resem- 
bling the  resounding  of  a  sonorous 
body,  as  a  bell  after  it  has  been 
struck) ;  we  call  the  phenomenon 
Phosphorescence,  not,  however, 
using  this  term  in  the  same  sense 
as  when  it  is  employed  in  connec- 
tion with  the  body  Phosphorus, 
which,  in  this  sense,  is  not  phos- 
phorescent. 

"  Sulphides  of  calcium  and  stron- 
tium, exhibit  this  action  in  the 
most  prominent  manner.  Such 
bodies,  exposed  to  a  strong  light, 
and  then  removed  to  a  dark  place, 
continue  to  glow  visibly  for  some  time.  The  same 
effect  is  also  very  beautifully  shown  in  some  Geissler 
tubes,  which  continue  to  emit  light  after  the  discharge  in 
them  has  ceased. 


GO 


LIGHT. 


This  is  noticed  in  the  form  shown  at  A  B,  in  Fig.  80. 

Dispersive  Power  is  the  term  applied  to  that  property 
of  unequally  refracting  the  different  colors,  by  which  the 
prismatic  spectrum,  and  other  similar  effects,  are  pro- 
duced. This  power  varies  with  different  bodies,  as  may 
be  seen  from  the  following  table : 


Table  of  Dispersive  Powers. 


Oil  of  Cassia  

0.139 

Turpentine 

0  042 

Sulphur  after  Fusion  

0.130 

Felspar  

0.042 

Phosphorus 

0  128 

0  041 

Sulphuret  of  Carbon  

0.115 

Amber  

0  041 

Balsam  of  Tolu  

0  103 

0  040 

0.093 

Oil  of  Rape-seed 

0  040 

Oil  of  Bitter  .Almonds  

0.079 

0  038 

Oil  of  Aniseed  

0.077' 

Olive-oil  

0  038 

Acetate  of  Lead,  fused  

0.069 

Gum  Mastic 

0  038 

Guaiacum  

0.066 

Beryl    

0  037 

Oil  of  Cumin  

0064 

JEther  

0.037 

Oil  of  Tobacco 

0  064 

Seleinte 

0  037 

0.063 

Alum  

0  036 

Oil  of  Cloves  

0062 

Castor-oil 

0  036 

Oil  of  Sassafras 

0  060 

0036 

Rosin  

0.057 

Water 

0  035 

Oil  of  Spearmint  

0.054 

Citric  Acid 

0  035 

Rock  Salt  

0.053 

Glass  of  Borax 

0  034 

Caoutchouc  

0.052 

Crown-Glass    ...         

0  033 

Flint-Glass  1st  sample 

0052 

Plate-Glass 

0032 

Oil  of  Thyme 

0  050 

Sulphuric  Acid 

0  031 

0  049 

Tartaric  Acid  . 

0  030 

Oil  of  Juniper        

0  047 

Nitre,  least  refr  

0.030 

Flint-Glass  2d  Cample 

0  047 

Borax 

0  030 

0  045 

0.029 

Canada  Balsam 

0.045 

Sulphate  of  Baryta  

0.029 

Oil  nf  Rhodium 

0  044 

Rock  Crystal 

0  026 

Oil  of  Poppy          

0.044 

Borax  Glass  (B.I,  Quartz  2) 

0.026 

Muriatic  Acid 

0  043 

Sulphate  of  Strontia  

0.024 

0  043 

0.022 

Nut  Oil..  .. 

0.043 

Cryolite  

0022 

LIGHT.  61 


Chromatic  Aberration.— Its  Correction. 

From  this  difference  in  dispersive  power  come  some 
important  results. 

We  readily  see  that  our  former  statements  about  lenses 
must  be  modified  with  regard  to  this  ;  namely,  that  beside 
other  irregularities  in  the  focussing  of  rays  where  light  is 
used,  the  violet  rays  would  oome  to  a  focus  much  nearer 
to  the  lens  than  the  red,  and  the  other  colors  at  various 
intermediate  points ;  so  that  from  this  cause  we  would 
have  an  ill  defined  image  fringed  with  color  which  would 
change  with  the  relative  position  of  the  screen  object  and 
lens.  Thus  at  Y  the  im- 
age would  have  a  border 
of  unfocussed  red  and 
other  rays,  and  at  R  of 
violet  and  other  ones. 
This  would  be  a  most 
fatal  error,  but  fortunate- 
ly it  may  be  corrected, 
thus  :  A  concave  lens  would  of  course  reverse  all  the 
effects  of  the  convex  one  A,  B,  and  would  disperse  the 
colors  in  an  opposite  direction.  Such  a  lens,  if  of  equal 
curvature,  would  therefore  exactly  neutralize  tire  disper- 
sion of  A,  B  ;  but  then  it  would  also  neutralize  the  refrac- 
tion, and  thus  make  the  lens  as  useless  as  a  flat  plate  of 
glass.  But  if  the  concave  lens  were  made  of  a  substance 
having  a  much  greater  dispersive  power  than  A  B,  then  it 
would  neutralize  the  dispersion,  even  though  of  less  cur- 
vature, and  thus  would  diminish,  it  is  true,  but  not  destroy 
the  refractive  action  of  A  B.  In  short,  it  would  make  it 
a  lens  of  longer  focus,  and  "  achromatic,"  that  is  without 
color. 

The  substance  commonly  used  for  this  purpose  is  flint- 
glass.     Combining  thus  a  double  convex  lens  of  crown- 
6 


62 


LIGHT. 


Fig.  50. 


glass,  with  a  piano  concave,  or  with  a  meniscus  lens  of 
flint  (there  being  here  two  refracting 
curves  for  the  crown,  and  one  for  the 
flint,  see  A  B),  or  by  uniting  two 
double  convex  lenses  of  crown,  with 
one  double  concave  of  flint,  see  C  D, 
we  obtain  what  are  called  "ACHRO- 
MATIC," Or  "CORRECTED  LENSES,"  which 
are  almost  free  from  irregularity  of  re- 
fraction. It  is,  however,  impossible  to  find  any  two 
bodies,  whose  refractive  and  dispersive  powers  so  exactly 
correspond  as  to  make  an  absolute  correction. 

Polarized  Light.  —  We  have  yet  another  point  to  con- 
sider about  the  nature  of  light.     Not  only  is  a  ray  of 
light  composite,  in  the  ways  already  mentioned,  but  also 
as  regards  the  plane  in  which  its  vibrations 
are  moving.     Thus,  a  ray  of  ordinary  light 
may  be  looked  upon  as  consisting  of  vari- 
ous series  of  undulations,  moving  in  every 
possible  plane  containing  its  line  of  direc- 
tion.    The  Across  section   of  such   a   ray 
would  be  represented  by  Figure  50,  the 
radial  lines  indicating  the  planes  in  which 
the  particles  were  vibrating.     By  various  means  we  may 
so  modify  and  "  sift  out"  these  vibrations, 
as   to   obtain    a   ray  in   which   all   are  in 
parallel  planes,   so  that  its  section  would 
be  represented  by  figure  51,  the  parallel 
straight   lines   representing   the  planes  in 
which  the  particles  are  vibrating. 

Plane  Polarized  Light  is  that  in  which 
all  the  vibrations  are  in  parallel  planes,  at  right  angles  to 
the  direction  of  the  ray. 

This  plane  polarized  light  (the   word  plane  is  often 


Fig.  51. 


LIGHT. 


63 


Fig.  52. 


omitted  for  brevity)  may  be  obtained  from  ordinary  light, 
in  one  of  the  three  ways  following : 

1st.  By  reflection  and  transmission.  If  a  ray  of  light 
falls  upon  a  transparent  reflecting  body,  such  as  water  or 
glass,  at  a  certain  angle,  differing  with  the  substance,  it  will 
be  partly  reflected,  and  partly  transmitted  ;  both  parts  will 
be  polarized  more  or  less  entirely,  the  one  transmitted, 
in  a  plane  perpendicular  to  the 
surface  of  the  reflector,  and  the 
reflected  one  at  right  angles  to 
this.  The  figure  will  give  a 
good  idea  of  this  action.  We 
here  assume  only  two  planes 
of  motion  in  the  ordinary  ray, 
for  convenience.  In  practice, 

of  the  other  vibrations,  those  nearest  one  plane  go  to  it, 
and  those  nearest  the  other  to  it;  or  escaping,  give  that 
mixture  of  ordinary  light  to  our  polarized  ray,  from  which 
it  is  never  entirely  free.  The  polarizing  angle  for  Glass 
is  3T°  35' ;  for  Water,  52°  45';  for  Quartz,  51°  32';  for 
Diamond,  68° ;  and  for  Obsidian,  56°  30'. 

2nd.  By  absorption.  If  a  ray  of  light  passes  through 
a  slice  of  the  mineral  tourmaline,  cut  perpendicularly  to 
its  axis,  all  its  vibrations,  except  those  in  one  plane 
are  absorbed  and  destroyed  within  the  crystal,  so  that 
the  emerging  ray  is  polarized.  The  iodo-sulphate  of 
quinine  in  crystals  possesses  this  same  property. 

3rd.  By  double  refraction. 
Whenever  a  ray  suffers  double 
refraction,  it  is  also  polarized, 
each  of  the  emergent  rays  being 
polarized  in  a  plane  at  right  an- 
gles to  the  other. 

NICHOL'S  PRISM  (see  page  50). 
Iceland  Spar  is  the  substance  used  in  preparing  polarized 


Fig.  53. 


64  LIGHT. 

light  in  this  way,  and  since  in  practice  it  is  desirable  to 
get  rid  of  one  of  the  two  rays,  the  crystal  is  cut  in  a  plane 
passing  through  its  obtuse  angles,  and  again  cemented 
together  with  Canada  balsam.  By  this  means  the  extra- 
ordinary ray,  A  B,  suffers  total  reflection  at  the  surface 
of  the  balsam,  and  is  thrown  out  at  the  side.  This  is 
called  a  Nichol's  Prism. 

Properties  of  Plane  Polarized  Light— These  may  be 
most  easily  understood  and  remembered  by  means  of  a 
simple  physical  illustration,  which  is  extremely  useful  as 
a  means  of  briefly  expressing  the  facts  of  the  case,  though 
in  no  respect  to  be  regarded  as  an  explanation  of  their 
final  cause. 

Suppose  that  light  rays  are  so  many  flat  rulers,  and 
that  polarizing  bodies  are  gratings,  whose  bars  are  par- 
allel to  the  planes  in  which  they  transmit  polarized  light. 
Then  an  ordinary  ray,  having  its  rulers  in  all  positions, 
coming  upon  one  of  these  gratings,  all  the  rulers  are 
"reflected,"  "absorbed,"  or  "  refracted,  out  of  the  way," 
except  those  which  are  parallel  to  the  bars  of  the  grating, 
and  which  therefore  get  through.  If  now  a  second  grating 
is  set  beyond,  parallel  to  the  first,  all  the  rulers  which 
have  passed  the  first  will  pass  it  also ;  but  if  this  second 
grating  is  set  at  right  angles  to  the  first,  the  rulers  will 
all  be  stopped  by  the  two ;  for  those  that  passed  the  first 
are  just  those  which  cannot  pass  the  second. 

Thus  it  is  in  fact  with  light.  If  we  place  two  polarizing 
bodies  in  the  path  of  a  ray,  it  will  pass,  if  both  are  par- 
allel, but  will  be  entirely  cut  off  if  they  are  "crossed." 
When  two  polarizing  bodies  are  used,  the  one  nearest  the 
light  is  called  the  POLARIZER,  and  the  other  the  ANALYZER. 

Thus  Fig.  54  represents  an  apparatus  for  developing 
the  effects  of  polarized  light.  Light  falls  upon  the  mirror 
A  B  from  the  left.  The  reflected,  polarized  ray,  which  is 
thrown  upward,  then  passes  through  the  tube  H  H,  which 


LIGHT. 


65 


H 


contains  an  analyzer,  Fig.  54. 

such  as  a  bundle  of 
glass  plates  placed 
obliquely  in  the  tube. 
If  these  last  are  paral- 
lel to  the  mirror  A  B, 
the  polarized  ray  will 
be  reflected,  and  will 
not  be  seen  through 
H  H  ;  but  by  turning 
this  tube  H  H  hori- 
zontally through  90° 
in  the  socket  G  Gr, 
on  which  it  rests,  the 
light  will  be  no  longer 
reflected,  but  will  be 
transmitted  by  the 
analyzer,  and  may  be 
seen  through  H  H. 
A  rotation,  however, 
of  90°  more,  or  180° 
from  the  starting 
point,  will  again  bring 
the  analyzer  into  a 
position  to  reflect  all 
the  polarized  light 
from  A  B  and  show 
none  of  it  through 
HH. 

Objects   to   be    ex- 
amined by   polarized 
light,  may  be  placed  in  the  ring  F  F.,  and  viewed  through 
the  analyzer  in  H  H.     Plates  of  doubly  refracting  sub- 
stances, display  splendid  colors,  and  sections  of  crystals, 
the  beautiful  iris  rings  to  be  presently  described. 
6* 


66 


Fig.  55. 


LIGHT. 

A  plate  of  doubly-refracting  substance 
may  be  regarded  as  a  grating,  with  two 
systems  of  openings  (Fig.  55)  at  right 
angles,  leading  off,  however,  in  different 
directions. 


Colored  Effects  of  Plane  Polarized  Light.  —  Suppose  a 
ray  of  ordinary  light,  A,  to  fall  upon  a  Nichol's  prism,  and 

Fig.  56. 


to  yield  a  plane  polarized  ray,  0.  If  this  ray  now  passes 
through  a  very  thin  plate  of  some  doubly  refracting  body, 
C,  placed  as  represented,  the  ray  will  be  split  into  two, 
p'  and  s';  one  of  which  will  be  retarded  behind  the  other, 
by  the  distance  of  part  of  a  vibration  (this  depending  on 
the  nature  and  thickness  of  the  film)  ;  but  these,  being  in 
different  planes,  cannot  interfere  with  each  other,  though 
they  will  be  so  little  apart  in  position  as  still  to  be  prac- 
tically together.  If  now  these  adjacent  yet  separate  rays 
fall  on  another  Nichol's  prism,  each  will  again  be  split, 
and  a  half  of  each  will  be  refracted  to  p'  s',  while  the 
other  halves  will  be  thrown  out  at  p"  s".  Now  p'  and  s' 
will  be  in  the  same  plane,  and  capable  of  interfering.  If 
then,  white  light  has  been  used,  and  the  retardation  of 
one  ray  behind  the  other  amounts  to  half  a  red  vibration, 
the  red  vibrations  in  p'  and  s'  will  interfere  and  destroy 
the  red  light ;  if,  however,  the  retardation  was  half  a  red 
vibration,  it  would  be  more  than  half  a  yellow  or  blue  one; 


LIGHT. 


67 


Fig.  57. 


hence  these  waves  would  not  interfere,  and  we  should 
have  green  light  at  p'  s'  by  the  removal  of  the  red.  If 
the  plate  C  were  thinner,  or  of  some  other  material,  the 
retardation  would  have  been  less ;  it  then  would  not  have 
destroyed  the  red,  but  some  other  color,  and  we  should 
therefore  have  something  else  than  green  at  p'  s'.  If  the 
principal  section  of  the  plate  C  was  parallel  or  perpendic- 
ular to  the  plane  of  polarization  of  the  light  0,  it  would 
pass  through  unchanged,  and  be  transmitted  or  not  by  D, 
according  as  B  and  C  coincided  or  not. 

If  instead  of  the  thin  plate  C  we  place  a  slice,  made  at 
right  angles  to  the  axis,  of  a  double  refracting  body,  in  the 
same  position,  with  a  diverging  beam  of  polarized  light, 
we  will  have  projected  on  a  screen  a  black  or  white  cross, 
intersecting  a  SA^stem  of  consecutive 
rainbow-colored  rings.  (See  figure  51.) 
The  cause  of  this  may  be  stated  as 
follows :  The  slice  of  crystal  may  be 
regarded  as  having  its  doubly  re- 
fracting properties  arranged  about  its 
centre ;  or,  to  give  it  a  physical  repre- 
sentation, as  having  openings  for  the 
passage  of  rays,  in  radial  and  circum- 
ferential directions,  as  in  the  figure  58. 
Suppose  now  the  polarized  light  to  be 
vibrating  in  a  vertical  plane,  its  vibra- 
tions will  pass  through  in  the  line 
M  N,  and  the  other  radial  lines  near  x' 
this,  without  change ;  so  also  through 
the  parts  of  the  circles  near  X'  Y, 
which  are  also  vertical ;  and  this  light 
will  then  either  be  stopped  or  transmitted  by  the  analyzer 
D,  according  as  that  corresponds  or  is  opposite  to  the 
polarizer  B.  This  will  then  give  the  black  or  white  cross. 
A  vertical  polarized  ray,  striking  at  R,  will,  however,  find 


Fig.  58. 


68 


LIGHT. 


Fig.  59. 


rz7 


no  direct  passage,  but  will  be  split,  part  going  through  the 
radial,  part  by  the  circular  passage.  These  divided  rays 
will  be  united,  and  will  produce  color,  as  in  the  case  of 
the  thin  plate  before  described.  Moreover,  the  divergent 
rays,  coming  on  this  plate,  will  have  to 
traverse  greater  thicknesses  the  further 
they  come  from  the  centre  (see  figure 
59) ;  thence  will  produce  different  colors, 
and  as  these  differences  will  vary  con- 
centrically about  the  axis  X,  the  colors 
will  be  disposed  in  rings,  intersected  by  the  crosses. 

The  best  specimen  for  this  experiment  is  a  plate  of  Ice- 
land spar,  about  one-twentieth  of  an  inch  thick,  well  pol- 
ished. Such  an  one,  placed  as  indicated  by  the  drawing 
Fig.  56,  in  a  good  gas  microscope,  with 
a  screen  about  20  feet  off,  gives  a  most 
charming  figure,  which  may  be  further  en- 
hanced by  adding  to  it  a  plate  of  quartz, 
similarly  cut  and  about  one-tenth  of  an 
inch  thick. 

Some  bodies,  such  as  nitre,  have  two 
axes  of  no  double  refraction  near  to- 
gether. Similar  slices  from  these  give 
double  systems  of  rings,  crossed  by  dark 
or  light "  brushes,"  produced  by  union  of  two  crosses.  (See 
Fig.  60).  Other  crystals  of  two  axes,  such 
as  sugar,  aragonite,  etc.,  have  these  so  far 
apart  that  only  one  system  of  rings  and 
brush  can  be  seen  at  a  time.  (See  Fig. 
61.) 

These   actions   of   polarized    light   are 
used  in  a  variety  of  ways   in  chemical 
investigations.     The  change  of  color  pro- 
duced by  polarized  light  in  many  bodies, 
crystalline  and  organic,  help  us  to  recognize  them ;  and 


Fig.  61. 


LIGHT.  69 

the  presence  of  these  crosses  or  colored  rings  are  simi- 
larly useful,  besides  helping  us  to  study  the  condition 
of  crystalline  bodies,  in  relation  to  their  condition  of  me- 
chanical strain. 

Blocks  of  glass,  gelatin,  etc.,  strained  by  pressure  or 
sudden  heating  or  cooling,  exhibit  colored  figures,  having 

Fig.  62. 


remarkable  analogy  to  those  of  crystals.  These,  when 
used  in  the  gas  microscope,  must  have  an  object-glass  in 
front  of  them,  between  them  and  the  analyzer. 

Rotation  of  the  Polarized  Ray. — If  in  place  of  the  slice 
of  Iceland  spar,  in  the  experiment  just  described,  we  put 
a  similar  plate  of  quartz,  cut  from  a  crystal  at  right  angles 
to  its  axis,  we  shall  have  a  system  of  colored  rings  as 
before,  but  instead  of  the  cross,  black  or  white,  the  central 
space  will  be  filled  with  colored  ligbt,  which  will  change, 
as  the  analyzer  D  is  rotated,  through  all  the  colors  of  the 
spectrum.  The  reason  of  this  is  as  follows :  This  sub- 
stance, though  like  others  it  does  not  produce  double  re- 
fraction along  its  axis,  etc.,  does  twist  the  plane  of  the 
polarized  ray,  giving  its,  edge,  as  we  may  say,  the  shape 
of  a  screw-thread.  The  amount  of  this  twist  is,  however, 
different  for  each  color.  Hence  in  each  position  of  the 


70  .LIGHT. 

analyzer  some  colored  rays  will  pass,  while  others  will  be 
stopped ;  thus  the  colors  are  produced. 

Some  specimens  twist  the  ray  in  one  direction,  others  iii 
the  opposite.  Those  which  so  turn  it  that  the  colors  change 
upward,  from  red  through  yellow,  green,  etc.  to  violet, 
when  the  analyzer  is  rotated  over  the  crystal  in  the  direc- 
tion that  watch-hands  move  over  its  face,  are  said  to  have 
right-hand  polarization,  or  to  be  dextrogyre ;  those  that 
change  oppositely  from  violet, -through  green,  etc.,  to  red, 
by  the  same  motion,  or  similarly  to  the  first  by  an  oppo- 
site motion,  are  said  to  have  left-hand  rotation,  or  to  be 
Iffivogyre. 

The  amount  of  this  polar  rotation  varies  with  different 
bodies,  and  in  the  same  body  with  its  thickness. 

This  power  of  rotation  belongs  to  other  solid  bodies 
besides  quartz ;  to  others,  as  Faraday's  heavy  glass,  it 
may  be  communicated  by  magnetic  action ;  and  it  also 
exists  in  some  liquids  and  solutions,  as  that  of  cane  and 
grape  sugar. 

Saccharimeter. — With  regard  to  these  substances  this 
property  is  used  as  a  commercial  test  of  value.  By  means 
of  an  appropriate  apparatus,  a  given  depth  of  solution, 
containing  a  known  quantity  of  the  sample  in  question,  is 
examined  by  polarized  light,  and  the  amount  of  rotation 
suffered  by  a  given  color  being  ascertained,  we  may  from 
this  estimate  the  quantity  of  the  corresponding  substance 
contained  in  the  solution.  Cane  sugar  has  right,  and  grape 
sugar  left-hand  rotation.  If  these  are  mixed  they  in  part 
neutralize  each  other's  effect ;  we  must,  then,  after  our  first 
determination,  convert  the  whole  into  grape  sugar  by 
hydrochloric  acid,  and  then,  having  made  a  new  determi- 
nation, settle  by  a  subtraction  the  original  proportion  of 
each.  This  process  may  be  applied  to  many  other  sub- 
stances. 


ELECTRICITY. 


71 


Fig.  63. 


Fig.  64. 


Circularly  Polarized  Light  is  that  in  which  the  vibra- 
tions are  in  two  planes,  at  right  angles  to 
each  other,  but  differing  also  in  phase  by 
an  odd  number  of  quarter-wave  lengths.    It 
may  be  produced  by  passing  a  ray  of  plane 
polarized  light,  through  a  Fresnel's  rhomb 
(Fig.  63),  when  suffering  two  total  reflec- 
tions at  an  angle  of  about  54°,  it  will  issue 
with  the  properties  required  for  circular  po- 
larization.    Circularly  polarized  light  may 
also  be  obtained  by  Airy's  method,  if  ordinary  light   is 
made  to  fall  vertically  on  a  film  of  mica 
or  selenite,  of  such  a  thickness,  that  the 
ordinary  ray  shall  be  retarded  more  than 
the  extraordinary  by  the  required  amount. 

With  circularly  polarized  light  the 
images  produced  by  slices  of  crystals  are 
changed,  the  black  cross  disappearing, 
and  the  alternate  segments  of  the  rings 
being  dislocated.  Thus,  for  Iceland  spar,  we  have  the 
Figure  64. 

Elliptically  Polarized  Light  is  that  in  which  the  vibra- 
tions are  in  two  planes,  perpendicular  to  each  other,  but 
differing  by  some  quantity,  not  an  exact  multiple  of  quar- 
ter-wave lengths.  This  is  obtained  from  a  Fresnel's  rhomb 
if  the  incident  and  refracted  rays  have  any  other  angle 
than  45°  between  their  planes ;  also  if  common  light  is 
reflected  from  a  metallic  surface. 

ELECTRICITY. 

We  indicate  by  this  term  the  cause  of  a  certain  class  of 
phenomena,  such  as  the  attraction  which  amber,  etc.,  pos- 
sesses for  light  bodies  after  being  rubbed,  the  lightning 
flash,  the  decomposition  of  bodies  by  a  galvanic  apparatus, 
the  polar  position  of  a  magnet,  etc. 


72  ELECTRICITY. 

Theory  of  the  Double  Fluid. —  In  giving  a  physical 
explanation  of  electric  phenomena,  and  connecting  them 
in  a  way  convenient  for  study  and  reference,  we  must 
begin  by  making  certain  assumptions,  which,  however,  it 
must  be  remembered,  have  no  other  proof  than  that  they 
serve  tc  connect  and  explain  the  phenomena  in  question. 

We  assume  that  all  space  and  all  matter  is  pervaded  by 
two  impalpable  fluids,  alike  in  general  character,  but 
having,  in  certain  respects,  exactly  opposite  properties ; 
that,  for  this  reason,  when  mingled  in  equivalent  quanti- 
ties, they  entirely  neutralize  each  other,  as  regards  these 
opposing  properties,  and  show  no  signs  of  their  existence 
(these  fluids,  together  or  separately,  may  perhaps  constitute 
that  aether,  to  which  we  have  before  alluded,  as  serving  tp 
transfer  the  vibratory  motions,  which  we  recognize  as  light 
and  heat).  These  opposite  electric  fluids  we  designate  as 
positive  (+),  and  negative  ( — ),  and  their  assumed  pro- 
perties may  be  very  briefly  stated. 

The  particles  of  each  fluid  are  mutually  repellant,  but 
attract  those  of  the  opposite  fluid,  and  of  matter  generally. 
They  are  capable  of  rapid  motion  or  transfer  through  some 
bodies,  as  metals,  moist  air,  etc.,  but  are  almost  precluded 
from  traversing  others,  as  glass,  shellac,  dry  air,  etc.  They 
may  be,  1st,  separated  and  confined  in  or  upon  certain 
bodies  ;  or,  2nd,  set  in  rapid  motion  in  opposite  directions ; 
or,  3rd,  caused  to  form  series  of  currents  in  the  individual 
particles  of  certain  substances.  These  three  conditions 
give  rise  to  three  divisions  of  our  subject,  Statical  Elec- 
tricity, Galvanism,  and  Magnetism. 

STATICAL  ELECTRICITY. 

By  this  term  we  indicate  that  condition  of  the  electric 
fluids  in  which  they  are  separated  more  or  less  completely, 
and  confined  for  a  greater  or  less  time,  to  certain  bodies. 

The  methods  by  which  this  separation  may  be  effected 


ELECTRICITY.  73 

are  numerous,  but  the  simplest  and  most  characteristic  is 
by  friction. 

If  two  different  substances  are  rubbed  upon  each  other, 
their  electric  fluids  will  be  more  or  less  separated ;  an 
excess  of  the  positive  fluid  collecting  in  one,  and  of  the 
negative  in  the  other.  Experiment :  Rub  a  glass  rod  with 
a  silk  handkerchief;  bring  the  rod  near  a  pith-ball  suspended 
by  a  silk  thread,  the  ball  will  be  attracted ;  so  also  will  it 
be  by  the  silk  (each  fluid  in  turn  attracts  the  matter  of  the 
ball).  Now  touch  the  ball  with  the  rod,  then  ball  and  rod 
will  have  the  same  fluid ;  hence  the  ball  will  now  be  re- 
pelled by  the  rod,  but  will  be  more  powerfully  attracted  by 
the  silk  than  before  (these  two  have  now  opposite  fluids 
which  attract).  In  this  case  the  glass  collects  the  positive 
fluid,  the  silk  the  negative. 

The  power  of  collecting  one  or  the  other  fluid  is  not 
positive  in  certain  substances,  but  simply  relative;  the 
body  which  takes  positive  and  loses  negative  fluid  by  friction 
with  one  substance,  will,  with  another,  take  negative  and 
yield  positive.  Arranging  all  substances  in  their  order  of 
positive  or  negative  attraction  we  would  have  a  table  like 
the  following,  in  which  any  substance,  rubbed  with  one 
below  it,  .will  take  positive  fluid,  but  rubbed  with  any 
above  it  will  take  negative  fluid.  This  is  what  we  mean 
by  calling  a  body  ELECTRICALLY  POSITIVE  or  NEGATIVE. 
The  bodies  at  the  beginning  are,  in  a  general  sense,  posi- 
tive ;  those  at  the  end  negative ;  but  any  substance  is 
positive  to  any  one  below  it,  and  negative  to  any  one 
above. 

Table  of  some  Substances  in  their  Electrical  Relations. 


Fur. 

Smooth  glass. 
"Woollen  cloth. 
Feathers. 


Paper. 

Silk. 

Lac. 

Rough  glass. 

Sulphur. 

Gun-cotton  and  like  bodies. 


74  ELECTRICITY. 

Conductors  and  Insulators. 

Bodies  through  which  the  fluids  easily  pass  are  called 
Conductors,  those  which  resist  their  motion,  Non-conduc- 
tors or  Insulators.  These  properties  are  relative,  as  we 
may  see  by  the  following  table,  which  begins  with  the 
best  conductors,  and  ends  with  the  worst,  which  is,  there- 
fore, the  best  insulator. 

In  the  following  list  the  bodies  are  arranged  in  their 
order  of  conducting  power,  according  to  the  present  state 
of  knowledge  on  the  subject,  and  though  probably  not 
absolutely  correct,  it  will  serve  to  show  how  insensibly 
conductors  and  non-conductors  merge  into  each  other :  — 


Table  showing  the  Relative  Conducting  Power  of  Certain  Substances 
for  Electricity. 


Metal,  best  conductor. 

Well-burnt  charcoal. 

Plumbago. 

Concentrated  acids. 

Powdered  charcoal. 

Dilute  acids. 

Saline  solutions. 

Metallic  ores. 

Animal  fluids. 

Sea  water. 

Spring  water. 

Rain  water. 

Ice  above  13°  Fahr. 

Snow. 

Living  vegetables. 

Living  animals. 

Flame  smoke. 

Steam. 

Salts,  soluble  in  water. 

Rarefied  air. 

Vapor  of  alcohol. 

Vapor  of  ether. 

Moist  earth  and  stones. 


Powdered  glass. 

Flowers  of  sulphur. 

Dry  metallic  oxides. 

Oils,  the  heaviest  the  best. 

Ashes  of  vegetable  bodies. 

Ashes  of  animal  bodies. 

Many  transparent  crystals,  dry. 

Ice  below  13°  Fahr. 

Phosphorus. 

Lime. 

Dry  chalk. 

Native  carbonate  of  barytes. 

Lycopodium. 

Caoutchouc. 

Camphor. 

Some  siliceous  and  argillaceous 

stones. 
Dry  marble. 
Porcelain. 

Dry  vegetable  bodies 
Baked  wood. 
Dry  grass  and  air. 
Leather. 


ELECTRICITY. 


Parchment. 

Dry  paper. 

Feathers. 

Hair. 

Wool. 

Dyed  silk. 

Bleached  silk. 

Raw  silk. 

Transparent  gems. 

Diamond. 


Mica. 

All  vitrifications. 

Glass. 

Jet. 

Wax. 

Sulphur. 

Resins. 

Amber. 

Shellac. 

Gutta  percha,  worst  conductor. 


The  Electrical  Machine. 


To  effect  this  separation  of  the  fluids  with  ease,  we 
employ  an  "  electrical  machine,"  which  consists  of  a 
glass  disk,  A,  mounted  on  an  axle,  and  turned  by  a 
handle,  of  a  "  rubber,"  B,  made  of  leather  spread, 
with  mosaic  gold  (bisulphide  of  tin),  and  supported  on 
a  glass  column ;  of  a  silk  apron,  E,  of  collecting  points, 
F,  and  of  a  round  ended  cylinder  of  metal,  Gr,  called 
the  "prime  conductor,"  supported  on  a  glass  column. 
The  positive  electricity,  developed  in  the  glass,  by  fric- 
tion on  the  rubber,  when  the  former  is  turned,  is  car- 
Fig.  65. 


ried  round   to   the   points,  being  protected  from  escape 
by  the  apron.     At  the  points  it  is  drawn  off  into  the 


76  ELECTRICITY. 

prime  conductor,  where  it  collects.  The  negative  elec- 
tricity accumulates  in  the  rubber.  To  get  much  positive 
electricity,  we  must  connect  the  rubber  with  the  earth,  by 
some  good  conductor ;  to  get  much  negative,  we  must  in 
like  manner  connect  the  prime  conductor,  insulating  of 
course  the  rubber. 

With  this  apparatus,  many  ingenious  experiments,  illus- 
trating the  attractive  and  repulsive  powers  of  unlike  and 
like  fluids,  may  be  performed,  such  as  the  dancing  images, 
the  sportsman  and  birds,  the  dancing  pith  balls,  the  in- 
dustrious spider,  the  electric  flyer,  and  orrery,  etc. 

Hydro-Electric  Machine, 

A   similar  separation   of   the   electric  fluids   may   be 
effected  by  the  friction  of  steam,  containing  particles  of 
water  in  suspension,  on  the    sides  of  peculiarly  shaped 
orifices.     (See   Fig.    66.)      In   this   case 
Fig.  66.  the  orifices  become  negative,  the  issuing 

steam  positive.  Points  placed  opposite 
the  escaping  steam  will  collect  the  posi- 
tive fluid.  Again,  by  the  dry  pile  to  be 
described  hereafter,  see  page  101,  this 
same  separation  is  effected ;  and  again, 
also,  by  the  Ruhmkorff  coil,  which  will 
be  described,  when  the  necessary  pre- 
liminary matters  have  been  discussed. 
(See  page  117.) 

Electrical  Attraction  and  Repulsion. 
The  first  effect  of  electricity  actually  observed,  and 
that  most  likely  to  excite  attention,  is  the  attraction  and 
subsequent  repulsion  of  light  bodies.  The  connection  of 
these  actions  with  our  theory  of  electricity  has  been 
already  explained,  page  12,  but  the  phenomena  them- 
selves may  be  strikingly  exhibited  by  the  following  pieces 


ELECTRICITY. 


of  apparatus  and  instruments  for  measurement  of  electric 
force : 
.  The  chime  of  bells  (Fig.  67)  consists  of  a  brass  rod, 


Fig.  67. 


A  B,  supported  by  a  stand,  and  connected  by  a  chain  or 
wire  with  an  electrical  machine.  From  each  end  of  this 
rod  hangs  by  a  chain  a  metallic  bell,  which  thus  receives 
electricity  from  the  machine.  Near  each  bell  hangs  by  a 
silk  thread  a  little  brass  ball  or  clapper,  which  is  attracted 
by  the  bell,  until  it  strikes  it,  when,  receiving  a  charge  of 
fluid,  it  is  repelled  in  turn,  but  attracted  then  by  a  centre 
bell  which  is  suspended  by  a  silk  cord  from  the  rod,  A  B, 
and  is  connected  with  the  ground  by  a  chain.  Each 
clapper,  as  it  strikes  this  bell,  therefore  gives  up  its  elec- 


78 


ELECTRICITY. 


tricity,  and  is  then  again  attracted  to  the  outer  bell,  so 
that  a  constant  motion  and  chiming  is  thus  maintained. 

The  dancing  pith-balls  (Fig.  68)  exhibit  a  like  action. 
The  balls  are  in  this  case  first  attracted  by  the  upper  plate, 
touch  it,  become  charged,  are  repelled  ;  strike  the  lower 
plate,  so  lose  their  charge,  are  again  attracted,  and  so  on. 


Fig.  68. 


Fig.  69. 


The  electrical  umbrella  (Fig.  69)  consists  of  many  strips 
of  colored  paper  connected  with  a  brass  rod,  which  may 
be  supported  on  the  prime  conductor  of  an  electrical  ma- 
chine. These  strips,  being  all  similarly  excited,  repel  each 
other,  and  so  stand  out  like  an  open  umbrella,  when  the 
machine  is  in  operation. 

On  a  similar  principle  is  constructed  the  quadrant  elec- 
troscope. In  this  the  brass  rod  fits  into  the  prime  con- 
ductor, and  has  attached  to  it  a  light  rod  with  a  pith-ball. 
This  being  charged  similarly  to  the  rod,  is  repelled  from  it, 


ELECTRICITY.  79 

the  amount  of  its  repulsion,  measured  on  a  small  quadrant, 
indicating  the  intensity  of  the  charge. 

This  is,  of  course,  but  a  rough  instrument ;  one  far  more 
delicate  is  furnished  in  the  gold-leaf  electroscope,  Fig.  70. 
Here  two  strips  of  gold-leaf  (Dutch  gold  is  best)  are  sus- 
pended from  a  brass  plate,  in  a  glass  vessel;  any  electric 
fluid  passed  into  them  causes  them  to  repel  each  other, 
and  so  diverge. 


Fie.  70. 


Fig.  71. 


A  more  delicate  instrument,  of  like  nature,  is  seen  in 
Coulomb's  electrometer,  Fig.  71.  In  this  case  a  light  rod 
of  gum  shellac  carries  at  one  end  a  pith-ball,  and  is  sup- 
ported by  a  fibre  of  silk,  the  whole  being  inclosed  in  a  glass 
vessel ;  a  small  brass  ball  terminates  a  wire  which  enters 


80  ELECTRICITY. 

this  vessel.  If  this  wire,  and  consequently  the  brass  ball 
is  excited,  it  first  attracts  the  pith-ball,  but  then,  after  con- 
tact, repels  it,  so  twisting  the  silk  fibre.  The  distance  to 
which  the  pith-ball  is  repelled  in  this,  as  in  a  former  case, 
indicating  the  intensity  of  the  electrical  excitement  in 
question. 

Distribution  of  Electricity. 

The  electric  fluids,  when  separated  as  above,  always 
reside  on  the  surfaces  of  bodies.  Thus,  in  non-conductors, 
they  cannot  penetrate  the  substance,  and  being  collected 
at  the  surfaces  must  remain  there;  and  in  conductors,  by 
reason  of  the  mutual  repulsion  of  like  particles,  they  are 
forced  outward  to  the  surface.  Opposite  fluids,  put  in  the 
same  conductor,  would,  of  course,  mingle  and  neutralize 
each  other.  By  reason  of  this  repulsion,  the  fluids  readily 
collect  on  and  escape  from  projections  and  points;  and 
similarly  enter  a  conductor  by  such  points  from  a  sur- 
rounding surcharged  medium. 

Thus  we  terminate  all  instruments,  intended  to  retain 
electricity,  with  rounded  surfaces,  balls,  and  the  like ;  but 
use  points  where  we  desire  to  introduce  the  fluids,  as  in 
the  collecting  points,  F,  Fig.  65,  of  the  electrical  machine 
(these  points  are  attached  to  the  brass  rods,  one  of  which 
is  shown  in  the  drawing,  along  their  inner  sides,  and  are 
directed  towards  the  glass  plate). 

So,  again,  with  LIGHTNING  RODS  ;  these  should  have 
sharp  points,  for,  if  thus  provided,  and  in  good  connection 
with  the  ground,  they  attract  and  gradually  withdraw  from 
the  approaching  thunder-clouds  their  charges  of  electricity, 
and  thus  often  prevent  a  "flash,"  as  well  as  divert  to  a 
safe  channel  those  not  to  be  so  obviated. 

That  electricity  occupies  alone  the  outer  surfaces  of 
bodies,  may  again  be  shown  if  we  provide  a  hollow  metallic 
sphere,  with  an  insulating  support  and  an  opening  by 


ELECTRICITY.  81 

which  its  interior  surface  may  be  reached.  Then,  when 
the  sphere  has  been  charged,  electricity  may  easily  be 
obtained  from  its  outer  surface  by  touching  it  with  a  "test- 
plane,"  i.  e.  a  little  button  or  wafer  of  brass  mounted  on  a 
glass  handle ;  while  none  can  be  obtained  by  this  means 
from  the  inner  surface.  The  "  test-plane,"  after  touching 
the  sphere,  should  be  brought  in  contact  with  the  plate  of 
the  electroscope,  Fig.  TO,  when  the  gold-leaves  will  diverge, 
if  any  electricity  has  been  received  by  the  planes. 

Induction  of  Electricity.  —  This  phenomenon,  like  the 
last,  is  the  direct,  necessary  consequence  of  those  general 
properties  of  the  electric  fluids,  stated  at  the  commence- 
ment of  this  subject. 

Thus,  suppose  a  conductor  charged  with  positive  elec- 
tricity, to  approach  an  insulated  conductor  in  the  natural 
state,  without  touching  it.  T^en  the  positive  fluid  in  the 
charged  conductor  will  drive  the  positive  fluid  in  the 
insulated  conductor  to  its  further  side,  and  draw  the 
negative  fluid  to  the  nearer.  The  fluids  would  in  this 
way  be  separated  in  this  insulated  conductor,  so  long  as 
the  charged  one  remained  near  it.  This  mode  of  sepa- 
rating the  fluids  we  call  "induction."  It  develops  some 
curious  consequences. 

The  Electrophorns.  —  Suppose  we  have  a  shallow  pan, 
filled  with  solid  shellac,  and  excite  this  negatively  by 
friction;  that  we  then  place  upon  it  a  plate  of  brass, 
varnished  with  shellac,  and  having  a  glass  handle.  The 
lower  face  of  this  will  become  Fig.  72. 

positive,  and  the  upper  negative, 
for  the  reasons  just  stated.  If 
now  we  connect  this  with  the 
ground  for  a  moment,  by  touch- 
ing it  with  the  finger,  the  repel- 
led negative  fluid  will  escape,  and 
some  positive  will  enter  to  fill 


82  ELECTRICITY. 

the  space  of  that  drawn  towards  the  shellac.  If  this 
plate  is  now  lifted  away  from  the  shellac,  by  its  glass 
handle,  it  will  clearly  have  in  it  an  excess  of  positive 
fluid,  which,  being  no  longer  held  to  one  place  by  an 
attraction,  can  pass  all  over  it  and  escape.  This  action 
can  be  repeated  without  loss  of  electricity  to  the  shellac, 
and  thus  furnishes  a  supply  of  that  agent,  which  admits 
of  many  ingenious  applications,  among  others  the  light- 
ing of  gas  burners,  as  in  the  many  forms  of  apparatus 
for  that  purpose,  invented  by  Robert  Cornelius,  Esq.,  of 
Philadelphia. 

The  Leyden  Jar.  —  We  have  already  noticed,  that  the 
electric  fluids,  by  reason  of  repulsion,  reside  on  the  sur- 
faces of  conductors,  and  tend  to  escape  therefrom.  Such 
bodies  are  thus  unfit  to  serve  as  reservoirs  of  this  agent, 
but  by  an  application  of  this  fertile  action  of  "  induction," 
the  difficulty  is  surmounted. 

We  coat  a  glass  jar  inside  and  out,  nearly  to  the  top, 
with  tinfoil.  We  close  the  mouth  with  a  cork  or  cover 
of  wood,  through  which  passes  a  rod,  connected  metalli- 
cally with  the  inner  coating.  Holding  the  jar  by  its  outer 
coating  in  the  hand,  or  otherwise  connecting  it  with  the 
ground,  we  then  pass  electricity  into  the  inner  coating, 
by  the  rod.  As  this  spreads  over  the  inner  coating,  it 
drives  away  a  corresponding  amount  of  the  same  fluid 
from  the  outer  coating,  and  draws  into  it  an  equiva- 
lent amount  of  the  opposite,  so  that  the  two  coat- 
ings become  oppositely  charged,  and  these  fluids, 
attracting  each  other,  do  not  tend  to  escape.  This 
apparatus  is  called  the  Leyden  Jar. 

A  number  of  these  having  their  outer  coatings 
united  by  strips  of  tinfoil  pasted  in  a  box  which 
contains  them,  and  their  inner  coatings  united  by 
brass  rods,  form  a  "  battery  of  Leyden  Jars."  To  use 
the  electricity  thus  stored,  we  make  such  a  connection 


ELECTRICITY. 


83 


Fig.  74. 


that  it  may  pass  from  one  to  the  other  coating,  through 
the  object  or  apparatus  we  wish 
it  to  traverse. 

Transfer  of  Electricity.— Elec- 
tricity may  pass  from  one  body 
to  another,  by  three  different 
methods;  by  conduction,  by  con- 
vection, and  by  discharge. 

Conduction  is  the  transfer 
through  particles  in  contact.  This 

takes  place  with  different  facility,  in  different  bodies,  as 
has  been  already  mentioned,  see  page  74,  and  also  varies 
with  the  temperature  of  the  same  body,  diminishing  with 
an  increase  of  heat.  Where  the  size  of  the  conductor  is 
sufficient  for  the  quantity  of  the  current  to  be  conveyed, 
no  change  is  produced ;  but  when  the  conductor  is  insuf- 
ficient, and  resists  the  passage  of  the  fluid,  heat  is 
developed.  Thus  a  large  battery  being  discharged  through 
a  strip  of  gold-leaf,  placed  between  two  plates  of  glass, 
melts  and  vaporizes  the  gold  ;  driving  it  into  the  glass, 
so  as  to  produce  a  purplish  stain.  So  with  a  fine  wire 
of  iron,  or  platinum,  etc. 

When  passing  freely  through  a  good  conductor,  elec- 
tricity moves  with  a  velocity  of  288,000  miles  per  second. 
This  was  measured  by  Wheatstone,  in  1834.  (See  Philo- 
sophical Transactions  for  that  year,  page  589.) 

Convection  is  the  transfer  of  electricity  by  motion  in 
particles  of  an  interposed  fluid,  such 
as  air.  Thus,  the  air  particles  touch- 
ing a  charged  conductor,  get  the  same 
fluid,  and  are  repelled,  move  off  to 
some  neutral  or  oppositely  charged 
body,  and  allow  others  to  take  their 
place.  These  in  turn  follow  the  same 
course,  a  current  is  established,  and 


Fig.  75. 


84  ELECTRICITY. 

the  electricity  is  thus  transferred.  This  may  be  well 
shown  by  attaching  a  pointed  wire  to  the  prime-con- 
ductor of  a  machine,  and  holding  a  burning  candle  or 
lamp  near  it.  The  flame  will  then  be  blown  aside,  if  not 
extinguished,  by  the  draft  of  air. 

Discharge  is  the  simultaneous  transfer  of  electricity 
developed  by  induction  in  the  particles  of  an  interposed 
non-conductor.  Thus,  particles  ABC  etc.,  in  a  given 
line,  being  excited  by  mutual  induction,  make  a  discharge 
when  A  gives  its  fluid  to  B,  at  the  same  time  that  B  gives 
its  own  to  C,  and  so  on.  This  transfer  may  be  more  or 
less  resisted,  and  its  character  thus  modified,  by  the  inter- 
posed substance.  We  accordingly  have  two  classes  of 
discharge,  the  disruptive  discharge,  flash,  or  spark,  where 
the  fluids  pass  through  a  highly  resisting  medium,  and 
the  diffused  or  flame  discharge,  where  the  medium  offers 
but  slight  resistance.  Between  these  there  may  be  every 
possible  gradation  ;  but  we  may  include  all  cases  in  one 
or  other  of  these  classes,  without  further  division. 

The  Disruptive  Discharge  is  seen  when  the  fluids  pass 
through  the  air,  as  in  the  ordinary  spark  from  the  machine, 
from  the  Leyden  jar,  from  the  induction  coil,  and  in  the 
lightning.  In  all  cases  it  is  accompanied  by  a  light  and 
sound,  both  varying  in  intensity  with  the  amount  of  elec- 
tricity which  is  passing.  The  color  of  the  light  varies 
with  the  points  between  which,  and  the  medium  through 
which,  it  passes.  In  all  our  experiments  the  spark  is  ac- 
companied by  a  transfer  of  the  material  of  which  the 
points  are  made,  and  it  is  only  reasonable  to  conclude 
that  the  light  owes  its  existence  to  the  vibrations  pro- 
duced in  these  particles,  as  they  are  torn  off  from  one 
point  and  thrown  towards  the  other. 

The  sound  is  caused  by  the  rapid  heating  and  cooling 
of  the  air  in  the  path  of  the  flash,  thus  producing  in  it 
such  a  vibration  as  will  affect  our  ears. 


ELECTRICITY. 


85 


Viewed  through  the  spectroscope,  the  light  of  this  dis- 
charge gives  only  bright  lines,  varying  with  the  sub- 
stances, showing  that  they  are  in  a  gaseous  state  when 
developing  this  light.  (Pro.  of  Roy.  Inst.,  1863,  p.  47.) 

Many  pretty  experiments  may  be  made  with  this  dis- 
charge—  as  the  lightning-jar,  the  lightning-plate,  the 
spark-plate,  the  letter-plate,  the  luminous  profile,  the 
lightning-house,  etc. 

This  spark  is  capable  of  igniting  many  compounds, — 
as  gun-cotton,  ether,  explosive  mixture,  burning  gas,  etc. ; 
but  will  not  fire  gunpowder,  unless  it  is  retarded,  as  by 
passing  through  a  wet  string.*  It  will  also  effect  many 
chemical  changes  of  combination  and  decomposition.  For 
igniting  most  of  these  bodies  we  place  them  upon  the 
table  of  the  universal  discharger,  Fig.  T6;  and  then  pass 

Fig.  76. 


*  In  this  experiment  the  wet  string  must  be  between  the  powder  and 
the  negative  coating 
8 


86 


ELECTRICITY. 


the  spark  through  by  means  of  the  adjustable  rods  c  d  f  g, 
supported  on  the  glass  columns  h  h. 

Liquids  like  ether  we  place  in  a  spoon,  and  take  a  spark 
into  it  by  a  wire  hung  from  the  prime  conductor  of  a  ma- 
Fig.  77. 


chine;  and  for  explosive  gases,  such  as  a  mixture  of 
oxygen  and  hydrogen,  we  use  a  little  brass  cannon  (Fig. 
78),  having  a  small  brass  rod  passing  through  a  glass  tube 

Fig.  78. 


into  it,  so  that  a  spark  entering  this  may  spring  across  to 
the  body  of  the  cannon  inside,  so  firing  the  contained 
gases,  and  driving  out  a  cork  placed  in  the  muzzle. 

If  an  egg  be  placed  upon  the  table  of  the  universal  dis- 
charger, Fig.  76,  and  the  spark  from  a  Leyden  jar,  or  the 
Ruhmkorff  coil,  be  passed  through,  it  will  be  illuminated 
in  a  remarkable  manner,  so  as  to  have  the  appearance  of 
being  red-hot. 

Its  vitality  is  of  course  destroyed,  but  it  is  otherwise 
uninjured  by  this  treatment. 


ELECTRICITY. 


87 


The  Glow  Discharge. — This  takes  place  when  the  inter- 
posed medium  offers  little  resistance  to  the  passage  of  the 
fluids.     This  is  well  seen  where  the  discharge  traverses 
rarefied  air,  gas,  or  vapor,  as  in  the  aurora  tube 
(Fig.  T9),  where  the  tall  glass  tube  is  exhausted 
by  the    air-pump,   and  then  has   its    caps    con- 
nected with  the  poles  of  a  Ruhmkorff  coil. 

The  color  of  the  discharge  in  this  case  is 
chiefly  effected  by  the  rarity  and  nature  of  the 
interposed  medium.  This  is  well  illustrated  in 
the  Geissler  tubes  (Figs.  80  and  81),  which  are 
filled  with  various  gases,  and  then  exhausted, 
by  means  of  a  mercurial  air-pump,  to  a  Torricel- 
lian vacuum,  or  nearly  so,  and  sealed.  If  now 
the  platinum  wires,  passing  through  their  ends, 
are  connected  with  the  poles  of  a  Ruhmkorff  coil, 
streams  of  beautifully  variegated  light  will  fill 
them,  crossed  by  obscure  bands.  With  hydrogen 
this  light  is  chiefly  pale  purple;  with  nitrogen 
pink,  with  a  violet-blue  glow,  filling  the  negative 
end  of  the  tube,  where  the  wire,  entering  the 
bulb,  will  be  coated  as  it  were  with  a  layer  of 
orange-colored  light.  Bulbs  of  Canary  glass 
placed  within  these  tubes,  as  in  C  D,  Fig.  80, 

Fiff.  80. 


88 


ELECTRICITY. 


glow  like  so  many  emeralds  amid  the  purplish  and  pink 
light  of  the  discharge.  In  some  cases  the  exhausted 
tubes,  bent  into  complex  forms,  are  surrounded  by  other 
tubes,  which  may  be  filled  with  various  fluorescent  or 
even  simply  colored  solutions.  Thus  in  Fig.  81  we  fill 
A  0  with  a  solution  of  quinine  and  B  D  with  nitrate  of 
uranium.  We  then  have  the  negative  ball,  say  F,  full 

Fig.  81 


c 


of  blue  light,  the  part  D  C  brilliant  rose-color,  F  purplish- 
pink,  and  the  portions  within  the  solutions  are  bordered 
from  A  to  C  with  a  magnificent  blue,  and  from  B  to  D 
with  a  rich  green  color.  The  single  tube  G  H  (Fig.  81) 
is  arranged  on  the  same  plan.  Simple  colored  solutions, 
such  as  bichromate  of  potash  and  sulphate  of  copper,  may 
be  used  in  place  of  the  fluorescent  ones,  with  equally 


MAGNETISM. 


89 


Fig.  82. 


beautiful  effect.     There  are  few  things,  if  any,  within  the 
range  of  philosophical  experiments  to  be 
compared  for  beauty  with  these  just  de- 
scribed. 

If  a  double  barometer  (Fig.  82)  has  its 
two  mercury  columns  connected  with  the 
poles  of  a  "coil,"  a  stream  of  light  will 
pass  through  the  arched  vacuum  above. 
This  light  will  be  white,  on  account  of  the 
vapor  of  mercury  present.  AN  ABSOLUTE 
VACUUM  (obtained  by  placing  caustic  pot- 
ash in  a  vessel  filled  with  carbonic  acid 
and  then  exhausted,  and  allowing  the  pot- 
ash to  absorb  the  last  trace  of  this  gas)  is 
totally  impervious  to  the  electric  dis- 
charge. If,  however,  the  potash  is  heated 
the  discharge  will  be  renewed,  the  slight 
vapor  produced  seeming  to  furnish  matter 
sufficient  for  this  action.  This  same  effect 
was  observed  with  the  intense  water-bat- 
tery of  3520  cells  used  by  Gassiot  as  well 
as  with  the  coil.  (Philosophical  Trans- 
actions, 1859,  p.  148. 


MAGNETISM. 

Magnetism  is  that  department  of  electricity  which  treats 
of  the  properties  of  magnets. 

A  magnet  is  a  body  which  has  the  power  of  attracting 
iron  and  some  other  metals,  and  of  setting  itself  in  a 
definite  position  with  reference  to  the  earth's  axis,  so  that 
one  end  points  toward  the  north  pole. 

According  to  our  theory,  a  magnet  owes  these,  and  its 
other  peculiar  properties,  to  the  fact  that  the  electric  fluids 
8* 


90 


MAGNETISM. 


Fig.  83. 


Fig.  84. 


in  its  various  particles  are  not  at  rest,  but  are  flowing  in 
opposite  directions,  making  a  series 
of  closed  circuits  in  each  particle. 
Regarding  for  simplicity  the  positive 
fluid  alone,  Fig.  83  would  indicate 
the  condition  of  a  magnet.  The 
small  spheres  representing  particles, 
and  the  arrows  showing  the  direc- 
tions of  the  currents  of  positive  fluid 
in  each.  The  negative  fluid  we 

suppose  to  be  forming  similar  currents  in  the  opposite 
direction.      With  the  direction  for  the  positive  current 
indicated  in  the  figure,  the  front  end  (to  the  right)  would 
be  the  South,  the  other  end  the  North 
pole.    These  directions  being  reversed, 
the  poles  would  be  reversed  also.    The 
aggregate  effect  of  all  these  currents 
would   evidently  be   nearly  identical 
with  a  close  spiral  around  the  surface, 
as  in  Fig.  84. 

Of  magnets,  we  have  —  natural  magnets  or  loadstones, 
artificial  magnets,  and  electro-magnets.  The  end  of  any 
magnet,  which  turns  towards  the  north,  we  call  its  north 
pole,  the  other  the  south  pole. 

Loadstone.  —  This  is  a  peculiar  ore  of  iron,  being  a  mix- 
ture of  the  proto  and  sesquioxide  of  iron  (FeO-j-Fe203), 
found  abundantly  in  nature,  and  possessed  of  the  magnetic 
properties  already  mentioned. 

Artificial  Magnet.  —  This  is  a  bar  or  rod  of  steel,  which 
has  received  magnetic  properties  by  being  rubbed  with 
another  magnet,  or  placed  within  a  spiral  galvanic  current. 
Such  a  magnet  will  possess  all  the  peculiar  properties  of 
the  natural  loadstone,  generally  in  intenser  degree. 

These  magnets  are  sometimes  made  in  the  shape  of 
straight  bars,  sometimes  they  are  bent  into  the  shape  of  a 


MAGNETISM. 


91 


horse-shoe  or  of  the  letter  U.  These  are  called  "  HORSE- 
SHOE or  U  MAGNETS."  They  gradually  lose  their  mag- 
netic properties  unless  a  bar  of  soft  iron  is  kept  across  their 
poles  as  S  JN",  Fig.  85.  This  bit  of  iron  is  called  an  "ARM- 
ATURE." A  magnetic  bar  made  light,  and  delicately 

Fig.  85. 


MAGNETISM. 


86- 


balanced,  so  as  to  turn  horizontally  about  a  point,  is  called 

"a  magnetic  needle." 

Two  such  needles,  fastened  one  over  the  other  with  re- 

versed poles,  form  an  as- 
tatic  needle,  which  will 
stand  east  and  west,  and 
be  deflected  by  a  very  fee- 
ble force,  see  Fig.  86.  In 
practice  astatic  systems 
are  so  constructed  as  to 
have  one  needle  more 
powerful  than  the  other; 
tneref°re  point  north 


Fig.  87. 


and  south,  but  can  be  de- 
flected by  very  feeble  forces. 

With  all  magnets,  like  poles  repel,  opposite  poles  attract. 

Besides  iron,  in  its  va- 
rious forms,  magnets 
attract  feebly  nickel, 
cobalt,  and  chromium ; 
and  very  powerful  mag- 
nets have  also  a  pecu- 
liar effect  on  all  other 
bodies,  causing  some  to 
arrange  themselves  in 
the  line  of  their  poles, 
and  others  at  right  an- 
gles to  this,  see  Fig.  87. 
The  first  are  called  MAGNETIC,  the  second  DIAMAGNETIC 
bodies.  Among  the  magnetic  substances  are  salts  of  iron^ 
even  in  solution,  as  also  those  of  chromium  and  manga- 
nese ;  among  the  diamagnetic  are  bismuth,  antimony, 
phosphorus,  most  gases,  and  organic  bodies. 

Electro-magnet. — This  is  a  bar  of  soft  iron,  around  which 
a  spiral  galvanic  current  is  made  to  pass,  as,  for  example, 


MAGNETISM. 


93 


in  a  bobbin  of  insulated  wire.  Such 
a  body  has  all  the  properties  of  a  mag- 
net so  long  as  the  current  continues, 
but  loses  them  the  moment  this  cur- 
rent ceases. 

In  electro-magnets  the  wire  is  gene- 
rally wound  entirely  outside  of  the  iron 
bar ;  so  that  the  current  produces  its 

Fig.  89. 


Fig.  88. 


effect  only  inwards.     A  very  ingenious  modification  has 
been  made,  however,  by  Mr.  Eben  Jayne,  in  which  the 


GALVANISM. 

ivhole  influence  of  the  current  is  utilized.  In 
this,  the  coil  is  wound  on  a*bar  of  iron  which 
forms  one  pole,  while  a  cylinder  of  iron,  slipped 
over  the  coil  and  joined  to  the  bar  at  one  end  by 
an  iron  cap  forms  the  other.  See  Fig.  90. 


Fie.  91. 


Magnetism  by  Induction.  —  Whenever  a  magnet  is 
brought  near  a  bar  of  iron  or  steel,  it  con- 
fers upon  it,  all  magnetic  properties.  The 
poles  of  the  induced  magnet  are  opposite 
to  those  of  the  inducing  one.  Thus,  if  the 
horse-shoe  magnet,  N  S,  have  two  iron 
keys  brought  near  it,  as  in  the  drawing, 
the  keys  will  be  magnetized  by  induction, 
with  poles,  as  shown  in  the  figure ;  and 
nails,  in  turn  brought  near  to  these,  would 
be  likewise  affected. 

If  the  body  once  magnetized  in  this  or 
any  other  way  is  of  steel,  it  retains  its 
magnetic  properties,  but  if  it  is  of  wrought  iron,  it  loses 
them,  as  soon  as  the  magnetizing  agency  is  withdrawn. 

GALVANISM. 

Galvanism  is  that  department  of  electrical  science  which 
treats  of  the  phenomena  first  pointed  out  by  Galvani  and 
Volta,  as  the  result  of  certain  connections  of  two  metals 
and  a  liquid,  and  of  other  actions  having  a  close  relation 
to  these  in  cause  and  character.  According  to  our  theory, 
we  believe  that  when  two  metals  are  immersed  in  a  liquid 
capable  of  acting  chemically  upon  one  of  them,  and  are 
connected  by  a  good  conductor,  as  the  chemical  decompo- 
sition of  the  liquid,  which  ensues,  progresses,  the  electric 
fluids  are  separated,  and  caused  to  pass  in  opposite  currents 


GALVANISM. 


95 


Fig.  92. 


through  the  circuit  of  the  materials  employed ;  the  positive 
fluid,  going  to  the  metal  least 
acted  upon,  thence  through  the 
conductor  to  the  other  metal, 
and  so  through  the  liquid  to 
the  starting-point  again ;  the 
negative  fluid  following,  mean- 
while, the  same  path  in  the 
opposite  direction. 

Such  a  combination  of  parts 
is  called  a  galvanic  " COUPLE;" 
many  of  these  connected  form 
a  "  BATTERY  ;"  couples  of  cer- 
tain forms  are  called  "CELLS." 
The  two  metals  or  their  equivalents  (for  non-metallic 
bodies  may  in  some  cases  be  used)  are  called  "  ELEMENTS  ;" 
the  one  most  acted  upon  being  always  the  positive  sub- 
stance (see  page  73)  ;  the  other  the  negative.  The  posi- 
tive fluid  will,  however,  always  come  out  from  the  nega- 
tive element.  The  fluid  used  is  commonly  called  the 

"EXCITING  LIQUID." 

In  the  following  table  each  substance  is  negative  with 
all  above,  and  positive  with  all  below  it,  when  placed  in 
galvanic  relation.  This  order  is  in  some  cases,  however, 
effected  by  the  nature  of  the  fluid  employed.  See  Phil. 
Transactions,  1840,  p.  113.  Diluted  sulphuric  acid  is  the 
exciting  liquid  assumed  in  the  table  here  given :  — 

Electro-chemical  Order  of  the  Principal  Elements. 


Electro-negative. 

Oxygen. 

Sulphur. 

Selenium 

Nitrogen. 

Fluorine. 

Chlorine. 

Bromine. 


Iodine. 

Phosphorus. 

Arsenicum. 

Chromium. 

Vanadium. 

Molybdenum. 

Tungsten. 

Boron. 


96 


GALVANISM. 


Carbon. 

Antimony. 

Tellurium. 

Titanium. 

Silicon. 

Hydrogen. 

Gold. 

Platinum. 

Palladium. 

Mercury. 

Silver. 

Copper. 

Bismuth. 

Tin. 

Lead. 

Cadmium. 


Cobalt. 

Nickel. 

Iron. 

Zinc. 

Manganese. 

Uranium. 

Aluminum. 

Magnesium. 

Calcium. 

Strontium. 

Barium. 

Lithium. 

Sodium. 

Potassium. 

Electro-positive. 


The  terminal  points  of  the  series,  where  the  connection 
outside  of  the  liquid  is  not  completed,  are  called  the  posi- 
tive and  negative  "  POLES"  or  "  ELECTRODES,"  according  as 
the  positive  or  negative  fluid  comes  from  them. 

Galvanic  Batteries. 

Omitting  those  forms  of  galvanic  batteries  which,  how- 
ever interesting  in  an  historical  connection,  are  not  prac- 
tically useful,  and  have  therefore  been  abandoned,  we  will 
describe  the  forms  now  generally  employed. 

Hare's  Calorimeter. 

This  consists  of  two  very  large  spirals  of  sheet  zinc  and 
copper,  wound  together,  in  close  proximity,  without  con- 
tact. This  is  accomplished  by  interposing  strips  of  card- 
board while  hammering  into  shape,  these  being  afterwards 
removed,  and  the  strips  sustained  and  kept  in  place  by 
wooden  bars,  as  indicated  in  the  Figures  93,  94,  95.  This 
pair  of  plates  is  then  immersed  in  a  tub,  bucket,  or  large 
jar  of  diluted  acid,  and  for  a  short  time  will  act  with  won- 
derful energy.  The  hydrogen,  liberated  by  the  decompo- 
sition of  the  water  (whose  oxygen  goes  to  the  zinc  form- 


GALVANISM. 

Fig.  93. 


97 


Fig.  94. 


ing  oxide  of  zinc,  which  is  then  taken  up 
by  the  acid),  at  once  attaches  itself  to 
the  copper-plate  in  countless  bubbles, 
which  not  only  interfere  with  the  con- 
ducting power  of  the  series,  but  present  a  positive  surface 
in  place  of  the  negative  copper,  thus  causing  the  battery 
rapidly  to  "  run  down,"  or  lose  strength. 

Smee's  Battery.  —  In  this  each  cell  consists  of  a  glass 
jar,  containing  diluted  sulphuric  acid,  in  which  hang  from 
a  cross-bar  of  wood  three  plates,  the  middle  one  of  pla- 
tinum, coated  with   a  deposit  of  the  same  metal  finely 
9 


98  GALVANISM. 

divided,  to  which  hydrogen  bubbles  will  not  adhere.  At 
each  side  of  this  hangs  an  amalgamated  zinc  plate. 
These  two  zinc  elements  are  united,  so  that  they  act  as 
one.  In  connecting  several  of  these,  the  zincs  of  one  cup 

Fig.  96. 


are  joined  by  a  wire  to  the  platinum  of  the  next,  and  so 
on.  In  place  of  platinum  plates  leaden  ones,  coated  first 
with  silver,  and  then  with  platinum  black,  may  be  em- 
ployed. This  battery  is  feeble  but  steady,  and  may  be 
charged  and  left  for  a  long  time  without  deterioration,  if 
the  connection  is  not  made  between  its  poles. 

Daniel's  Battery. — In  this  each  cell  consists  of  a  copper 
vessel,  containing  a  solution  of  sulphate  of  copper ;  within 
this  a  porous  cell  or  cup  of  unglazed  earthenware,  con- 
taining diluted  sulphuric  acid,  in  which  is  immersed  a 
cylinder  of  zinc.  The  hydrogen  liberated  in  this  case 
passes  into  the  sulphate  of  copper,  decomposing  it  and 
throwing  down  metallic  copper,  by  combining  with  the 
oxygen  of  the  oxide  of  copper  in  the  salt,  so  forming 
water.  This  battery,  therefore,  gives  off  no  gas  at  all, 
and  (some  crystals  of  sulphate  of  copper  being  placed  on 
a  shelf  in  the  outer  vessel  to  restore  the  solution  as  it  be- 
comes impoverished)  is  very  constant.  It  is,  however, 
feeble,  as  compared  with  the  following  forms. 


GALVANISM. 


99 


Fisr.  97. 


Grove's  Battery. — In  this  each  cell  consists  of  an  outer 
jar,  containing  diluted  sulphuric  acid,  in  which  is  set  a 
hollow  cylinder  of  zinc ; 
within  this  is  a  porous  cup, 
filled  with  strong  nitric 
acid,  in  which  hangs  a 
slip  of  platinum  foil.  The 
hydrogen  liberated  in  this 
case,  passing  into  the  nitric 
acid,  takes  some  of  its  oxy- 
gen from  it  to  form  water, 
leaving  it  as  nitric  oxide, 
which  at  first  dissolves  in 
the  acid,  and  when  that  is 
saturated  escapes  in  fumes. 
The  decomposition  of  the 
nitric  acid  developes  an  in- 
crease of  force,  which  ren- 
ders this  the  most  powerful 

form  of  constant  battery  yet    1,.^^ mmmmM 

invented. 

Bunsen's  Battery.  —  This  battery  differs  from  the  last 
only  in  the  substitution  of  solid  bars  or  cylinders  of 
"  gas-carbon  "  for  the  platinum  foil. 
This  is  dictated  by  economy.  The 
best  form  of  this  battery  for  rapid 
handling  is  that  manufactured  by 
Deleuil,  of  Paris.  The  cokes  are 
hollow  cylinders,  very  porous,  and 
connection  is  made  by  copper 
plugs,  which  can  be  forced  into 
the  ends  of  these,  and  are  joined 
to  copper  strips  riveted  to  the 

zincs.     Connections    can    be    made    and   broken   by  this 
means  with  greater  ease,  certainty,  and  dispatch   than 


Fig.  98. 


100  GALVANISM. 

with  the  best  form  of  binding  screws ;  and  this,  in  the 
management  of  a  large  battery,  is  of  great  importance. 
For  telegraphic  purposes,  however,  the  battery  made  by 
Chester  &  Co.,  of  New  York,  is  better  than  this. 

Modified  Forms  of  the  Bunsen  Battery. — Chester  &  Co., 
of  New  York,  manufacture  a  Bunsen  battery,  which  an- 
swers very  well  for  medical  applications,  in  which  the 
gas-coke  is  made  into  a  cup  in  which  the  zinc  is  supported, 
the  exciting  fluid  being  a  solution  of  sulphate  of  mercury. 
This  gives  off  no  fume  and  uses  no  seriously  corrosive 
liquid.  Its  energy  and  constancy  are  increased  by  addi- 
tion of  a  little  table-salt.  An  ordinary  Bunsen  cell  will  act 
in  a  similar  manner,  for  a  short  time,  if  the  porous  cell  is 
removed,  and  a  solution  of  glauber  salt  (NaO,S03)  is  em- 
ployed as  the  only  exciting  liquid.  (See  Journal  of  the 
Franklin  Institute  of  Pennsylvania,  Yol.  50,  p.  68,  1865.) 

Chester  &  Co.  also  manufacture  another  form  of  the 
same  battery,  under  the  title  of  "  electropoion  battery." 
The  important  feature  in  this  is  the  substitution  of  a  mix- 
ture of  sulphuric  acid  and  solution  of  bichromate  of  pot- 
ash for  the  nitric  acid.  This  removes  the  difficulty  of  acid 
fumes,  and  relieves  a  great  expense,  the  cost  of  this  mix- 
ture being  about  one-tenth  that  of  nitric  acid.  A  good 
recipe  for  this  mixture  is  this  :  in  a  gallon  of  water  dissolve 
10  oz.  of  bichromate  of  potash ;  to  this  add  one  pint  of  oil 
of  vitriol.  (See  Journal  of  Franklin  Institute,  Yol.  50, 
page  68.) 

This  battery  works  very  well  with  the  Ruhmkorff  coil, 
and  also  for  the  electric  light. 

The  Iron  or  Maynooth  Battery.  —  In  this,  each  cell  con- 
sists of  an  iron  cup,  containing  a  mixture  of  equal  parts 
of  nitric  and  sulphuric  acids,  within  this  is  a  porous  cup, 
filled  with  dilute  sulphuric  acid,  and  containing  a  plate  of 
amalgamated  zinc.  The  best  form  of  this  battery  is  that 
manufactured  by  Bullock  and  Crenshaw,  of  Philadelphia, 


GALVANISM.  101 

in  which  the  iron  cups  are  rectangular,  and  the  zincs  of 
rolled  metal. 

This  is  the  cheapest  form  of  battery ,  and ^ equal,, if ,ii9t, 
superior,  to  any  other  of  equal  soj/a^o^yi^ejfeict.  ;-'^  -/^  ^ 

We  must,  however,  in  this  connection  remark  that  the 
mixture  of  strong  nitric  and  sulphuric  acids  here  used 
gives  off  a  most  acrid  and  irritating  fume  less  during  the 
action  than  during  the  charging  and  emptying  of  the 
battery.  Arrangements  should,  therefore,  be  made  for  a 
strong  draft  or  current  of  air  to  carry  these  fumes  away 
from  the  operator  during  this  process.  The  best  plan  is  to 
conduct  it  in  the  open  air. 

The  electro-motive  forces  of  some  of  the  preceding  bat- 
teries have  been  estimated  as  follows : 


Bunsen  element 839 

Grove  829 


Smee  210 

Hare...  ..  208 


Daniel 470 

Besides  those  already  mentioned,  very  many  other  com- 
binations of  solids  and  liquids  have  been  suggested  for 
galvanic  batteries,  but  none  others  have  proved  in  prac- 
tice successful.  Thus,  we  have  copper  and  carbon  with 
the  mixture  of  bichromate  of  potash  and  sulphuric  acid 
already  mentioned.  Copper  and  zinc  with  S03  and  flowers 
of  sulphur.  The  Bunsen  solids  with  sesquichloride  of 
iron,  etc. 

The  Dry  Pile,  invented  by  Zamboni,  consists  of  many 
thousands  of  alternate  disks 
of  zinc  and  silver  paper ;  or 
of  silver  paper,  with  a  paste 
of  black  oxide  of  manganese 
and   gum,    spread    on    the 
wrong    side,    without    the 
zinc;  arranged  in    a  glass  \^     PTF^-.- 
tube    or    other    insulating 
support.     (See  Fig.  99.) 
9* 


102 


GALVANISM. 


The  natural  moisture  of  the  paper  here  serves  the  office 

of  an  exciting  fluid,  and 
very  intense,  though 
feeble  effects  are  pro- 
duced. Thus,  the  ex- 
tremities will  attract  light 
bodies,  and  even  give 
minute  sparks  ;  exhibit- 
ing in  fact  rather  the 
effects  of  statical,  than 
of  dynamical  electricity. 
This  results  from  the 
great  number  of  ele 
ments,  and  bad  conduct 
ing  power  of  the  pile, 
which  favors  a  separation 
of  the  fluids,  but  not  the 
establishment  of  a  cur- 
rent. One  of  the  piles, 
thoroughly  dried,  ceasee 
to  act;  but  recovers  on 
exposure  to  moist  air. 
A  double  column  of  this 
sort  arranged  as  in  (Fig. 
100)  will  keep  the  light 
ball,  a,  vibrating  between 
its  poles  for  years. 
Gas  Battery.  —  See  page  109. 

Management  of  Galvanic  Batteries.  — Where  a  number 
of  cells  are  to  be  used  together,  they  should  be  united  in 
different  ways,  according  to  the  effects  which  we  desire 
to  obtain.  If  great  resistances  are  to  be  overcome,  as  in 
the  electric  light,  the  heating  of  fine  wire,  etc.,  they 
should  be  placed  in  a  series,  as  indicated  by  (Fig.  101), 
where  a  Bunsen  battery  is  shown  in  ground  plan,  the 


GALVANISM. 


103 


carbon  of  each  cell  being  connected  with  the  zinc  of  its 
right  hand  neigh- 
bor.    This  gives  Fis- 10L 
us   a  current   of 
intensity,     great 
in  proportion   to 
the    number    of 

the   cells   (within   certain  limits),  and  of  quantity,  pro- 
portional to  the  size  of  a  single  cell. 

If  the  resistance  to  be  overcome  is  very  small,  as  when  the 
current  has   only  to  pass 
through  a  short  and  good 
conductor,  the  cells  should 
be   united,   as    shown    in 
(Fig.    102),   all  the   zincs 
being  joined   together   at 
one  side,  and  the  carbons 
at  the   other ;    then,   con- 
necting Z  and  C,  we  obtain  a  current,  whose  intensity  is 
only  that  of  a  single  cell,  but  whose  quantity  is  pro- 
portional to  the  number  of  cells  employed. 

Usually  we   require  in  electrical   apparatus,  some  in- 
tensity, with  as  much  quantity  as  we  can  get.     A  good 


Fig.  102. 


Fig.  104. 


Fig.  103. 


practical  arrangement  for  ordinary  apparatus   is    shown 
(Fig.  103),  and  for  a  Ruhmkorff  of  9  inch  spark,  or  under, 


104  GALVANISM. 

in  Fig.  104.  For  larger  coils  the  series  should  be  in- 
creased in  quantity,  but  not  in  intensity,  until  we  come 
to  the  large  coils  of  16  to  20  inches,  when  15  cells  should 
be  used,  in  three  rows,  giving  intensity  of  three,  and 
quantity  of  five. 

In  setting  up  a  nitric  acid  battery,  it  is  most  conveni- 
ent to  mix  the  dilute  acid  in  the  cells  beforehand,  then 
to  put  in  all  other  parts,  and  make  the  connections ;  and 
lastly,  to  pour  in  the  nitric  acid.  This  prevents  the 
dulling  of  the  connections  by  fumes,  and  saves  nitric 
acid  ;  as  the  cells  get  soaked  with  the  diluted  sulphuric 
acid  beforehand. 

The  mixed  liquids  to  be  used  should  always  be  mixed 
beforehand,  and  allowed  to  cool  entirely. 

In  all  large  batteries  the  connections  should  have  as 
much  contact  surface,  and  be  as  large  in  section,  as  pos- 
sible. 

After  use,  the  battery  should  be  taken  apart,  as  soon 
as  possible.  More  injury  will  occur  to  a  battery,  while 
standing  disconnected,  than  when  it  is  in  active  use;  as 
the  local  currents  have  at  this  time  full  play.  The  zinc 
elements  should  be  well  washed,  drained,  and  kept  (apart 
from  the  other  portions  of  the  battery)  in  as  dry  a  place 
as  possible.  The  porous  cells  and  carbons  should  be 
kept  in  water,  if  to  be  used  soon  again,  and  soaked  for  at 
least  a  week  (in  water  frequently  changed),  before  being 
dried  and  put  away.  To  put  away  porous  cells,  etc. 
(which  have  been  simply  washed  after  use),  in  contact 
with  the  zinc  elements,  is  to  insure  great  injury,  and 
perhaps  even  destruction,  to  the  battery. 

Carbons  used  with  such  batteries  as  that  described, 
page  100,  should  be  soaked  in  diluted  nitric  acid,  when 
they  become  coated  with  a  white  deposit  of  oxide  of  zinc, 
or  the  like. 

Amalgamation.  —  Zinc  is  the  active  element  employed 


GALVANISM.  105 

in  all  batteries,  and  on  account  of  certain  impurities 
which  cannot  be  removed,  but  by  very  expensive  treat- 
ment, is  subject  to  "  LOCAL  ACTION  ;"  that  is,  a  little  speck 
of  some  foreign  substance  will  form,  with  the  zinc  im- 
mediately around  it,  a  little  galvanic  pair,  which  will 
cause  a  rapid  corrosion  of  the  zinc,  formation  of  hydrogen 
bubbles,  interference  with,  and  opposition  to  the  general 
current  of  the  battery,  and  other  evils.  To  remedy  this 
difficulty,  we  resort  to  amalgamation  ;  that  is,  coating  the 
surface  of  the  zinc  with  mercury,  which  unites  with  it, 
and  practically  excludes  all  such  local  action  as  we  have 
described,  preventing,  in  fact,  to  a  great  degree,  any 
chemical  action  between  the  liquid  and  metal,  until  the 
entire  galvanic  circuit  is  closed,  and  the  true  chemico- 
electric  action  begins. 

Batteries  in  use  should  be  thoroughly  amalgamated. 
This  is  best  done  some  days  before  they  are  to  be  set  up, 
as  zincs  freshly  amalgamated,  sometimes  heat,  and  suffer 
local  action,  in  an  unaccountable  manner. 

Effects  of  the  Galvanic  Currents. 

Heating  and  Luminous.  —  We  have  already  noticed  that 
a  wire  is  heated  by  a  current,  which  it  is  unable  to 
conduct,  and  that  the  discharge  of  a  battery  of  Ley- 
den  jars  will  thus  fuse  and  vaporize  gold,  iron,  plati- 
num, etc.  (page  83).  Similar  effects  are  produced  by  a 
galvanic  current.  Thus,  the  current  from  40  Bunsen  cells, 
8  inches  high,  will  keep  6  feet  of  platinum  wire,  No.  2  T,  at 
a  bright  red  heat,  3  feet  at  a  white  heat,  and  will  fuse  a 
shorter  piece.  By  cooling  part  of  the  wire,  as  with  a  wet 
cloth,  we  make  the  rest  hotter;  because  more  electricity 
can  pass  by  the  cool  wire,  heat  diminishing  the  conducting 
power.  The  surrounding  medium  has  a  certain  effect  on 
this  experiment,  for  a  draft  of  air  will  cool  the  wire ;  as 


106  GALVANISM. 

also  will  such  a  gas  as  hydrogen,  on  account  of  the  mo- 
bility of  its  particles. 

Luminous  Effects.  —  When  a  very  powerful  series,  of  30 
or  40  elements,  is  terminated  by  points  of  dense  carbon, 
and  these,  being  first  in  contact,  are  separated  a  little,  a 
most  dazzling  light  is  produced.  In  this  case  particles  of 
the  carbon  are  driven  across  from  the  positive  to  the  nega- 
tive pole,  causing  such  vibrations  as  produce  intense  light 
to  take  place  in  both  the  points,  and  to  some  extent  in  the 
flying  particles.  This  may  be  admirably  shown  where  the 
points,  regulated  as  they  burn  away  by  Duboscq's  Electric 
Lamp,  are  placed  in  a  lantern,  and,  through  a  diaphragm, 
throw  an  enlarged  inverted  image  of  themselves  on  the 
screen. 

If  the  lower  or  positive  point  in  the  lamp  is  replaced  by 
a  cup  of  carbon,  holding  a  fragment  of 
silver,  and  the  discharge  is  taken  from 
this,  the  light  given  off  is  green,  the 
length  of  the  discharge  is  increased  5 
times,  and  the  negative  point  becomes 
beaded  with  drops  of  liquid  silver,  car- 
ried over  by  the  current.  On  the 
screen  we  see  the  image  shown  at 
Fig.  105. 

The  flame,  emerald  green,  and  like 
a  tongue  licking  the  point,  now  on  one 
side,  now  on  another :  the  points  red,  tipped  with  white, 
and  the  silver  drops,  like  so  many  beads  of  dew. 

This  discharge,  called  the  electric  light,  when  produced 
from  a  single  series  of  48  Bunsen  elements,  is  equal  to  572 
candles.  By  increasing  the  number  of  elements  in  series 
above  this,  the  gain  in  intensity  of  light  is  small,  though 
the  arch  of  flame  may  be  made  longer;  thus  46  elements 
give  an  intensity  of  235,  and  80  elements  of  238.  But  by 
increasing  the  quantity,  as  by  using  three  parallel  series 


GALVANISM.  107 

of  36  elements,  the  intensity  rises  to  385  ;  that  of  sunlight 
being  1000. 

We  have  reason  to  believe,  from  certain  spectral  lines 
and  fluorescent  effects,  that  the  intensity  of  heat  and  light 
in  the  electric  discharge  is  greater  than  in  the  sun.  See 
Paper  by  Wm.  A.  Miller,  in  Proceedings  of  Royal  Insti- 
tute, 1863,  p.  47. 

Chemical  Effects  of  the  Galvanic  Current. 
If  the  poles  of  a  galvanic  battery  are  placed  in  any  com- 
pound fluid  they  tend  to  separate  it  into  its  constituents, 
the  positive  being  attracted  to  and  collecting  around  the 

Fig.  106. 


negative  pole,  and  the  negative  about  the  positive  pole. 
Thus,  if  we  have  a  U  tube,  with  a  solution  of  sulphate  of 
soda  colored  by  tincture  of  cabbage,  and  plunge  two  plati- 
num strips,  forming  the  terminals  of  a  battery,  in  the  ends, 
the  acid  or  negative  element  of  the  salt  will  collect  about 
the  positive  pole,  turning  the  cabbage-purple  red  in  that 
lin.b,  while  the  alkali,  or  positive  constituent,  will  collect 
about  the  negative  pole,  and  turn  the  purple  of  that  limb  to 
a  rich  green.  Again,  if  the  fluid  contains  but  two  "ele- 
ments," as  water  (consisting  of  oxygen 


108 


GALVANISM. 


Fig.  107. 


these  will  likewise  be  separated  and  eliminated.    Thus  the 

glass  vessel,  Fig.  107, 
containing  water,  and 
having  two  platinum 
strips  let  into  it  below, 
connected  with  the 
battery",  the  oxygen 
will  be  given  off  at  the 
positive  pole,  and  the 
hydrogen  at  the  nega- 
tive, and  these,  rising 
in  bubbles,  may  be 
collected  in  tubes  ar- 
ranged for  the  pur- 
pose. 

This  action,  called 
ELECTROLYSIS,  is  in- 
deed our  most  potent 
means  of  effecting  the 
decomposition  of 
chemical  bodies.  So- 
dium, potassium,  etc., 
were  discovered  by 
this  means  ;  by  this 
means  also  we  mea- 
sure the  quantity  of  a 

galvanic  current,  the  amount  of  water  decomposed,  and  of 
gas  evolved,  being  in  proportion  to  the  quantity  of  the 
current  passing,  we  therefore  have  an  apparatus,  arranged 
like  the  preceding,  except  that  both  gases  are  collected 
together  and  measured,  the  amount  collected  in  a  given 
time,  indicating  the  quantity  of  the  current.  Figs.  108 
and  109  show  two  forms  of  this  apparatus.  The  first  is 
the  most  complete  and  efficient,  but  the  second  is  the 
simplest  and  most  easy  of  construction.  The  cork  and 
wires  must  be  well  coated  with  sealing  wax. 


GALVANISM. 
Fig.  108. 


109 


The  great  industrial  ap-  Fig- 109. 

plication  of  this  same  action, 
in  electro-plating  and  gild- 
ing and  electrotyping,  must 
not  be  forgotten.  Here,  the 
matrix  or  mould  being  made 
of,  or  covered  with  a  con- 
ducting material,  is  suspend- 
ed in  a  solution  of  the  metal 
to  be  deposited,  and  made 
the  negative  pole  of  a  gal- 
vanic series.  The  positive 
metal  is  then  deposited  on 
this  in  so  solid  a  state  as  to 
form  a  complete  plating,  or 
admit  of  being  itself  removed  and  used  for  printing,  etc., 
as  the  case  may  be. 

Gas  Battery  and  Secondary  Piles. 
After  the  apparatus,  Fig.  86,  has  been  used  for  a  few  mo- 
ments, if  it  is  disconnected  from  the  battery  and  connected 
with  a  delicate  galvanometer,  a  current  will  be  shown,  op- 
10 


lllllllllllllllilllliillillllilllillE. 


110 


GALVANISM. 


posite  to  that  of  the  original  battery.  This  is  produced 
by  films  of  oxygen  and  hydrogen  attached  to  the  platinum 
plates.  On  this  principle  Grove  constructed  his  gas  bat- 
tery. So  also  powerful  "secondary  piles"  may  be  pro- 
duced by  immersing  two  or  more  plates  of  lead  in  a  solu- 
tion of  Glauber  salt,  connecting  the  end  plates  with  a  bat- 
tery, and  after  a  time  disconnecting. 

Properties  of  Currents  Moving  Freely  in  Wires, 

Magnetizing  Effects.  —  We  have  already  noticed  that  a 
current  passing  around  a  bar  of  iron  renders  it  a  magnet, 
permanently  if  the  bar  is  of  steel,  temporarily  if  the  bar 
is  of  soft  iron  (page  92).  This  action  is  well  shown  in 
many  pieces  of  apparatus,  such  as  the  divided  ring,  the 
armature  engine,  &c. 

Fig.  110. 


The  most  remarkable  application  of  this  action  is,  how- 
ever, found  in  the  first  telegraph  practically  applied,  i.  e. 
that  of  Morse  (Fig.  110).  In  this  an  intermittent  current 
(whose  breaks  and  flows  are  controlled  by  an  operator  at 


GALVANISM. 


Ill 


one  end  of  a  long  circuit),  causes,  at  the  other  end,  an  ar- 
mature or  bar  of  soft  iron,  attached  to  a  lever,  to  be  re- 
peatedly attracted  by  an  electro-magnet  set  beneath  it,  and 
thus  makes  a  pencil  at  the  other  end  of  this  lever  produce 
upon  a  moving  band  of  paper,  dots  by  a  short  and  strokes 
by  a  more  continued  pressure.  An  alphabet  of  these  marks 
being  pre-arranged  between  two  operators,  communication 
may  be  thus  made  through  great  distances  with  indefinite 
velocity. 

By  ingenious  and  elaborate  arrangements  of  mechanism, 
the  message  sent  is  automatically  printed  by  the  apparatus, 
as  in  the  instrument  of  House  or  of  Hughes,  and  is  even 
in  that  of  Bain  reproduced  in  an  autographic  copy. 

Velocity  of  Galvanic  Currents  in  Good  Conductors, 

This,  according  to  experiments  of  the  U.  S.  Coast  Sur- 
vey, is  about  18.100  per  second  in  land  lines,  but  through 
submerged  cables  the  velocity  is  much  less. 

Magnetic  Properties  of  Coils  or  Solenoids. 


Fig.  111. 


As  might  be  antici- 
pated from  the  theory  of 
magnets,  a  coil  or  solen- 
oid (Fig.  Ill)  through 
which  a  current  is  pass- 
ing, has  all  the  proper- 
ties of  a  magnet.  It 
will  attract  iron,  repel 
with  its  poles  the  like 
and  attract  the  unlike 
poles  of  magnets,  ar- 
range itself  north  and 
south,  and,  in  fact,  comport  itself  in  all  respects  like  a 
magnetic  bar. 


112 


Fig.  112, 


GALVANISM. 

Again,  such  a  Coil  will  tend  to  draw  into 
itself  a  bar  of  iron  whose  end  is  brought  within 
its  reach.  This  is  well  illustrated  by  the  ex- 
periment of  the  suspended  bar  (Fig.  112),  and 
by  Page's  coil  engine,  in  which  bars  attached 
to  cranks  and  alternately  drawn  into  coils,  are 
caused  to  operate  machinery. 

Again,  such  a  Coil  will  cause  a  magnetic 
needle  to  stand  at  right  angles  to  the  planes  of 
its  circular  currents.  This  principle  is  app)ied 

Fig.  113. 


GALVANISM.  113 

in  the  apparatus  used  for  measuring  the  intensity  of  cur- 
rents ;  for  the  amount  of  deflection  will  vary  in  a  known 
ratio  to  the  intensity  of  the  current.  For  currents  of 
small  quantity  the  GALVANOMETER  (Fig.  113)  is  used. 
This  consists  of  a  heavy  flattened  coil  of  wire,  within  and 
over  which  an  astatic  pair  of  needles  is  suspended.  The 
deviation  of  these  is  noted  on  a  circular  graduated  scale, 
when  a  current  is  passed  through  the  coil  by  means  of  the 
binding  screws. 

For  currents  of  great  quantity  we  employ  the  Tangent 
Compass  (Fig,  114),  which  consists  of  a  band  of  copper, 
bent  nearly  into  a  ring,  supported  on  a  stand,  with  a 
binding  screw  attached  to  each  end,  and  with  a  small 
compass-needle  supported  at  the  centre.  With  this  in- 
strument the  intensity  of  the  current  is  proportional  to  the 
tangent  of  deflection  of  the  needle. 

A  Solenoid  will  be  acted  upon  by  a  current  in  this,  as  in 
other  respects,  exactly  like  a  magnetic  needle.  By  reason 
of  this  "  tangentical  force,"  also,  a  wire  carrying  a  current 
tends  to  revolve  about  a  magnet  parallel,  or  nearly  par- 
allel to  it. 

Again,  a  Magnet  will  likewise  rotate  around  a  current — 
as  may  be  proved  in  a  similar  manner — and  also  around 
a  current,  passed  through  half  its  own  length. 

Many  effects  similar  to  the  foregoing  may  be  developed 
by  the  magnetic  action  of  the  earth,  and  may  be  readily 
explained,  on  the  principles  already  stated,  by  regarding 
the  earth  as  a  great  magnet,  with  its  north  pole  (in  a 
magnetic  sense)  at  the  south,  and  the  south  pole  at  the 
north  extremity  of  its  axis. 

Wires  carrying  currents  in  the  same  direction  attract 
each  other. 

Wires  carrying  opposite  currents  repel  each  other. 

A  conductor  carrying  a  current  between  the  poles  of  a 
10* 


114 


GALVANISM. 
Fiar.  114. 


II  magnet,  at  right  angles  to  the  line  joining  them,  is  re- 
pelled. 

Galvanic  Induction.  By  Currents  and  Magnets.— If  two 
wires  are  placed  parallel  to  each  other,  and  an  intermit- 
tent current  is  passed  through  one  of  them,  at  every  in- 
terruption of  the  flow  an  instantaneous  "  INDUCED  or 


GALVANISM. 


115 


SECONDARY  CURRENT,"  coincident  in  direction  with  the 
first  or  "PRIMARY  CURRENT,"  will  be  developed  in  the 
other  wire.  At  every  renewal  of  the  primary,  on  the 
other  hand,  a  momentary  induced  current  will  be  devel- 
oped in  the  other  or  "  secondary  wire,"  opposite  in  direc- 
tion to  the  "primary." 

These  induced  currents  may  be  best  shown  by  using 
coils  or  helixes  of  wire,  wound  on  spools  or  bobbins. 
Thus  we  have  a  large  bobbin  of  fine  wire,  A,  for  the 

Fig.  115. 


secondary,  and  a  smaller  one,  B,  of  thick  wire,  fitting  into 
the  former,  for  the  primary  current. 

These  being  put  in  place,  and  an  intermittent  current 
passed  through  B,  the  secondary,  developed  in  A,  may 
be  demonstrated  by  connecting  its  ends  with  a  galvanom- 


116  GALVANISM. 

eter,  or  by  holding  them  in  the  hands,  when  a  shock  or 
series  of  shocks  will 'be  perceived. 

A  like  effect  would  be  produced  if,  in  place  of  interrupt- 
ing the  current  in  B,  we  left  it  continuous,  and  then  rap- 
idly moved  B  out  of  and  into  A. 

A  magnet  may  be  similarly  used/as  a  substitute  for  B, 
being  thrust  into,  and  withdrawn  from  A,  with  the  same 

Fig.  116. 


effect ;  or  we  may  place  a  bar  of  soft  iron  in  A,  and  then 
cause  it  to  receive  and  lose  magnetism  by  the  approach 
and  withdrawal  of  a  permanent  magnet.  This  will  of 
course  be  precisely  equivalent  to  inserting  and  withdrawing 
it.  This  is  the  principle  of  action  in  the  magneto-electric 
machine,  Fig.  116,  and  others  of  like  nature.  By  such 
means,  many  magnets  being  employed,  currents  are  ob- 


GALVANISM. 


Ill 


Fig.  117. 


tained  capable  of  electro-plating  on  the  large  scale,  of  illu- 
minating light-houses  with  the  electric  light,  etc. 

Lastly,  we  may  put  B  in  its  place,  insert  a  soft  iron  bar 
in  the  centre  of  it,  and  then  pass  a  discontinuous  current 
through  B ;  we  shall  then  have  the  combined  inductive 
eifect  of  the  coil  and  magnet.  This  is  realized  in  the  or- 
dinary medical  induction  coil 
(Fig.  117).  A  bar  of  iron 
may  have  excited  on  its 
surface  an  induced  current, 
which  interferes  with  its  in- 
fluence on  the  secondary 
coil.  For  this  reason  a  bundle  of  needles  is  more  effective 
than  a  bar.  If  these  needles  are  surrounded  by  a  con- 
ducting envelope,  such  as  a  tube,  their  efficiency  is  again 
reduced,  unless  this  tube  has  a  longitudinal  opening  to 
interrupt  its  conducting  power. 

A  secondary  helix,  like  that  just  described,  if  made  of 
very  great  size,  constitutes  the  apparatus  known  as  the 
Ruhmkorff  coil,  which  yields  a  secondary  current  of  so 
great  intensity  as  to  possess  all  the  properties  of  statical 

Fig.  118. 


118  GALVANISM. 

electricity.  This  coil,  as  originally  constructed  by  Ruhm- 
korff,  is  shown  (Fig.  118)  as  improved  by  E.  S.  Ritchie,  Esq., 
of  Boston,  in  Fig.  119.  (See  Franklin  Institute  Journal, 
vol.  40,  p.  64.) 

Fig.  119. 


To  both  these  coils,  when  a  great  resistance  is  to  be 
overcome,  as  when  the  spark  is  to  be  passed  in  air,  the 
"  condenser"  of  Fizeau  is  an  addition  of  great  importance. 
This  consists  of  two  sheets  of  tinfoil  of  great  extent,  40  to 
100  square  feet,  separated  by  oil  or  gummed  silk,  folded 
away  in  compact  form  (in  general,  packed  in  the  base  on 
which  the  rest  of  the  apparatus  is  supported),  and  con- 
nected with  the  primary  circuit,  at  each  side  of  the  point 
where  it  is  interrupted.  This  condenser  delays  the  action 
of  the  extra-current  (to  be  presently  described),  and  so 
enables  the  electricity  to  collect  and  overcome  a  resist- 
ance before  this  interfering  action  can  take  effect.  Where 
the  resistance  is  small,  as  in  discharges  in  a  vacuum,  or 
through  good  conductors,  the  condenser  is  not  required. 
The  largest  coils  of  this  sort  contain  30  miles  of  wire  in 
the  outer  helix,  and  give  sparks  of  20  inches  in  length. 


GALVANISM.  119 

This  coil  is  at  once  the  most  convenient  and  powerful 
means  of  producing  statical  electricity  within  our  reach. 
With  6  to  10  Bunsen  cells,  one  of  .Ritchie's  6  to  15  inch 
coils  will  produce  a  continuous  stream  of  sparks  6  to  15 
inches  in  length  ;  will  charge  a  large  Ley  den  jar,  so  that  it 
will  be  discharged  with  a  report  like  a  torpedo  many  times 
in  a  second ;  and  will  operate  all  electrical  vacuum  experi- 
ments with  a  splendor  and  volume  of  light  entirely  unap- 
proached  by  any  other  electrical  apparatus.  It  is  not, 
however,  fit  to  perform  experiments  of  attraction  and  re- 
pulsion, because  the  fluids  are  developed  in  it,  not  steadily, 
but  in  a  series  of  instantaneous  flashes. 

The  Extra-Currents.— This  is  the  name  given  to  induced 
currents,  similar  to  those  above  described,  which  are 
developed  in  a  primary  wire  at  the  moment  of  making 
and  breaking  connection.  The  inverse  extra-current,  de- 
veloped at  making  connection,  is  of  course  overcome  by 
the  opposing  primary  then  started ;  but  the  "  direct"  extra- 
current  produced  at  breaking  circuit,  shows  itself  very 
fully.  It  occasions  the  bright  spark  seen  at  breaking  con- 
nection, where  the  circuit  passes  by  a  long  wire,  espe- 
cially if  this  is  coiled,  and  may  be  made  to  give  a  shock, 
fuse  platinum  wire,  etc.,  exactly  as  the  ordinary  induced 
current  would. 

It  is  often  used  in  medical  batteries,  and  is  then  gener- 
ally called  "the  primary  induced  or  Henry  current." 

Currents  are  also  induced  by  magnets  in  moving  con- 
ductors.     Thus,  a 
copper  disk   being 
rotated     under     a 
compass       needle, 
will  have  currents 
developed     in     it, 
which,  by  their  ac- 
tion on  the  needle,  will  cause  it  to  revolve  about  its  point 
of  support. 


120 


GALVANISM. 


Again,  a  disk  of  copper  rotated  between  the  poles  of  a 
powerful  magnet  becomes  very  hot  by  reason  of  the  cur- 
rents developed  in  it ;  in  fact,  Tyndall  using  a  brass  tube 
in  this  way  has  melted  fusible  metal  in  it  in  l£  minutes. 


Fig.  121. 


Thermo-Eleetricity. 

If  two  different  metals,  such  as  Bismuth  and  Antimony, 
united  at  one  point,  be  heated  at  this  junction,  a  current 
of  electricity  will  be  established  between  them  in  one 
direction ;  if  they  are  cooled  in  the  same  place  the  current 
will  be  reversed.  If,  therefore,  many  such 
bars  be  joined  alternately,  as  in  Fig.  120, 
B  heated  at  one  side,  A  B,  and  cooled  at  the 
other,  C  D,  a  sort  of  battery  will  be  pro- 
duced, and  a  strong  current  obtained.  The 
flow  thus  developed  is  called  Thermo  Elec- 
tricity, but  is  in  all  respects  identical  with 
the  galvanic  current  of  the  battery.  In  the  following 
table  many  substances  are  arranged  in  order,  from  the 
most  positive  Bismuth  to  the  most  negative  Tellurium. 
Any  one  of  these  will  be  positive  to  any  below,  and  nega- 
tive to  any  above  it;  that  is,  when  heated  with  one  below 
the  positive  fluid  would  pass  to  that  other  metal  by  the 
junction,  and  so  on.  Here,  as  in  the  battery,  however, 
the  positive  pole  will  be  connected  with  the  negative  ter- 
minal element 


Bismuth, 

Nickel, 

Cobalt, 

German -Silver, 

Brass, 

Lead, 

Tin, 


Copper, 

Platinum, 

Silver, 

Zinc, 

Iron, 

Antimony, 

Tellurium. 


According  to  Bunsen  and  Becquerel  (see  Jour,  of  Fr. 


GALVANISM. 


121 


Fig.  122. 


lust.,  Yol.  49,  p.  422),  the  most  powerful  series  of  any  may 
be  made  of  copper,  pyrites,  or  sulphide  of  copper,  and  me- 
tallic copper. 

This  development  of  electricity  by  heat 
may  be  well  shown  by  the  thermo-elec- 
tric revolving  arch,  Fig.  122,  where  the 
lamp,  heating  the  junction  of  the  brass 
ring  with  the  iron  arch,  causes  a  current 
which  rotates  the  frame,  so  as  to  bring 
the  other  junction  into  the  lamp,  when 
the  same  thing  is  repeated,  and  a  rota- 
tory movement  is  thus  kept  up. 

This  action,  by  which  heat  develops  a 
galvanic  current,  is  of  great  use  in  the 
measurement  of  very  delicate  variations 
of  temperature ;  for  by  connecting  a  small  thermo-electric 
combination  or  pile,  as  Fig.  123,  with 
a  delicate  galvanometer,   changes  of 
temperature  may  be  noted  which  would 
otherwise  escape  all  observation.    Such 
an    arrangement  is  called  a  THERMO- 
MULTIPLIER,  and  is  of  inestimable  value 
in  most  branches  of  physical  research. 


Animal  Electricity. 

Some  fish,  such  as  the  Raia  torpedo,  and  the  gymnotus 
or  electrical  eel,  by  reason  of  a  peculiar  anatomical  struc- 
ture within  their  bodies,  in  some  sort  resembling  a  gal- 
vanic pile,  develop  notable  quantities  of  electricity,  so  that 
they  give  a  very  severe  shock  if  touched,  and  may  be 
caused  to  magnetize  a  bar  of  iron,  fuse  gold-leaf,  etc. 
Though  this  intense  and  special  manifestation  of  electric 
11 


122  GALVANISM. 

disturbance  is  confined  to  a  few  creatures,  provided  with 
a  peculiar  set  of  organs,  electrical  action  goes  on  in  some 
degree  in  all  living  animals,  and  is  closely  connected  with 
their  vital  actions.  Thus  electric  currents  can  be  proved 
to  exist  in  the  muscles  when  these  are  in  action,  and  a  sort 
of  galvanic  battery  can  even  be  produced  by  connecting  in 
order,  many  portions  of  muscular  substance. 

The  subject  of  animal  electricity,  in  its  relation  to  phy- 
siology, is  one  of  great  interest ;  but  it  is  as  yet  too  much 
mixed  with  doubtful  theory,  and  too  extended  in  its  scope 
for  discussion  in  this  place. 


ABC      D        Ei>     E 


Ba 


HS.Du-v«J&-  SonI«ithPhila,d?. 


PART  II. 


CHEMISTRY. 

General  Definitions. 

Chemistry  is  that  science  which  treats  of  the  distin- 
guishing properties  of  bodies  and  of  their  actions  under 
the  influence  of  CHEMICAL  AFFINITY. 

Distinguishing  Properties  are  those  possessed  by  certain 
substances  exclusively,  and  by  which  they  may,  therefore, 
be  recognized.  Ex.  Gold  has  a  specific  gravity  of  19.26, 
a  yellow  color,  and  melts  at  2016°  F. ;  these  properties 
make  it  distinguishable  from  other  substances. 

Chemical  Affinity  is  that  force  of  attraction  which  exists 
between  the  particles  of  substances  of  a  different  nature, 
causing  them  to  unite  so  as  to  form  compounds,  having 
properties  unlike  those  of  the  constituents. 

1st.  It  acts  between  particles,  i.  e.  only  at  insensible 
distances,  thus  requiring  an  intimate  mixture  or  approach 
of  particles  to  bring  them  within  its  range.  Thus  sulphur 
and  chlorate  of  potash  mingled  in  lumps  effect  no  combi- 
nation, but  if  ground  together  in  a  mortar  a  violent  com- 
bination takes  place  (a  few  grains  only  should  be  used 
for  this  experiment).  From  this  fact  arises  the  utility  of 
pulverization,  fusion,  and  solution  in  conducting  chemical 

actions. 

(123) 


124  CHEMISTRY. 

2nd.  It  acts  between  substances  of  a  different  nature. 
Thus  acids  will  combine  with  alkalies,  and  vice  versa,  but 
not  acid  with  acid,  or  alkali  with  alkali.  As  a  general 
rule,  the  more  different  the  properties  of  the  substances, 
especially  in  an  electrical  sense,  the  greater  their  force  of 
combination. 

3rd.  It  causes  the  formation  of  compounds  with  prop- 
erties different  from  those  of  their  constituents.  These 
differences  are  chiefly  in  (a)  Color,  (6)  State,  (i.  e.  solid 
liquid  or  gaseous),  (c)  or  in  Temperature. 

(a)  To  illustrate  changes  in  color.  Prepare  seven  glasses 
containing  solutions  in  water  of  the  following  substances  : 
I.  Ferrocyanide  of  potassium.  II.  Chromate  of  potas- 
sium. III.  A  mixture  of  the  foregoing.  IY.  Sulpho- 
cyanide  of  potassium.  Y.  Hydrosulphate  of  Ammonium. 
YI.  Sulphuric  Acid.  YII.  Ammonia.  To  each  of  these 
add  a  solution  of  nitrate  of  lead  containing  a  little  sesqui- 
nitrate  of  iron.  The  colors  then,  originally  light  yellow 
or  white,  will  become  as  follows  :  I.  Blue,  II.  Yellow,  III. 
Green,  IY.  Red,  Y.  Black,  YI.  Milk-white,  YII.  Buff. 
Two  blacks  make  a  white.  Make  some  ink  in  a  glass  by 
mixing  in  it  tincture  of  galls  and  per-sulphate  of  iron. 
Drop  into  it  some  crystals  of  chlorate  of  potash.  Make 
some  common  sulphuric  acid  black,  by  stirring  it  with  a 
stick.  Pour  the  black  acid  into  the  ink,  and  a  clear  solu- 
tion like  water  will  result. 

(6)  Changes  in  state.  Two  solids  make  a  liquid.  Grind 
together  in  a  mortar  crystals  of  NaOS03*  (6  parts)  and 
NH4  0,N05  (5  parts).  They  will  form  a  liquid.  Mingle  a 
saturated  solution  of  CaCl.  with  a  little  oil  of  vitriol  dilu- 
ted with  half  its  bulk  of  water.  These  clear  liquids  will 
form  an  opaque  solid.  Two  gases  make  a  solid.  Rinse 
one  glass  with  a  few  drops  of  Ammonia  and  another  with 

*  NaOS03  =  Glauber  salt  NIT40;N05  =  Nitrate  of  Ammonia.  CaCl  = 
Chloride  of  Calcium. 


INORGANIC    CHEMISTRY.  125 

Muriatic  acid.  Place  their  openings  together;  they  will 
be  filled*  with  solid  particles  forming  a  dense  cloud. 

(c)  Differences  in  temperature.  Pour  oil  of  vitriol  into 
water,  introduce  a  test  tube  containing  water,  and  stir  it 
about.  The  water  in  this  will  boil.  Pour  water  on  an- 
hydrous CuO,S03*  or  on  Lime  (CaO.);  both  will  become 
intensely  hot  and  give  off  steam.  The  laws  which  govern 
this  force  will  be  found  on  page  295. 

Substances  are  of  two  kinds: 

Inorganic  or  mineral,  as  metals,  gases,  rocks,  &c.,  and 

Organic,  or  those  connected  with  "  life,"  as  wood,  flesh,  &c. 

Organic  bodies  differ  from  inorganic  in  so  many  ways 
that  they  are  best  considered  separately  under  the  head 
of  Organic  Chemistry.  Moreover  this  branch  of  the  sub- 
ject can  be  developed  more  clearly  after  we  have  explained 
the  laws  which  regulate  the  formation  of  the  much  sim- 
pler substances,  in  the  domain  of  Inorganic  Chemistry. 

INORGANIC  CHEMISTRY. 

Inorganic  bodies  are  either  Elements,  Binaries,  Terna- 
ries or  Quaternaries. 

1st  Elements  are  those  bodies  which  have  never  been  de- 
composed or  separated  into  others.  Their  number  is  about 
65,  of  which  50  are  METALS  and  15  METALLOIDS  or  non- 
metallic  elements.  The  following  table  contains  a  list  of 
these  elements,  with  their  symbols  and  atomic  weights, 
combining  proportions  or  equivalents.  The  names  in  brack- 
ets are  those  from  which  the  equivalents  of  certain  bodies 
have  been  derived :  6  of  these  are  metals  known  to  the 
ancients  and  still  retaining  in  this  sense  their  Latin  names, 
Sb  Au  Fe  Pb  Hg  St.  Two  discovered  in  modern  times 
follow  their  example,  and  one  takes  its  name  from  a  Ger- 
man mineral  in  which  it  was  first  found. 

*  CuOS03=  Sulphate  of  Copper. 
11* 


126 


INORGANIC    CHEMISTRY. 

Table  of  the  Elements. 


Names  of  Elements. 

1 

Al 
Sb 
As 
Ba 
Bi 
B 
Br 
Cd 
Cs 
Ca 
C 
Ce 
Cl 
Cr 
Co 
Cu 
D 
Er 
F 
Gl 
Au 
H 
I 
In 
Ir 
Fe 
Ln 
Pb 
Li 
Mg 
Mn 
Hg 
Mo 

1! 

Names  of  Elements. 

S 

| 

i  § 

29.6 
97.5 
14 
99.6 
8 
53.3 
31 
98.7 
39 
52.6 
85.4 
52.2 
39.3 
21.35 
108 
23 
43.8 
16 

68.8 
64.2 

204 
59.5 
59 
24.3 
92 
60 
686 
32.2 
32.6 
33.6 

Aluminum 

13.7 
120.3 
75 
68.5 
208 
10.9 
80. 
56 
133 
20 
6 
46 
35.5 
26.7 
29.5 
31.7 
48 

19 

26.5 
197 
1 
127 
27.07 
99 
28 
47 
103.7 
7 
12 
27.6 
100 
47.88 

Nickel 

Ni 
Nb 
N 
Os 
0 
Pd 
P 
Pt 
K 
Ro 
Rb 
Ru 
Se 
Si 
Ag 
Na 
Sr 
S 
Ta 
Cb 
Te 
Tb 
Tl 
Th 
Sn 
Ti 
W 
U 
V 
Y 
Zn 
Zr 

Antimony  (Stibium)  
Arsenic  

Niobium    . 

Nitrogen  

Barium  

Osmium  

Bismuth 

Oxygen 

Boron 

Palladium 

/  /Bromine 

Phosphorus 

Cadmium     ... 

Platinum  ... 

Ceesium  

Potassium  (Kalium). 
Rhodium  

Calcium  

^Carbon 

Rubidium 

Cerium  . 

Ruthenium 

Chlorine      

Selenium  ... 

Chromium  

Silicon  

Silver  (Argentum).... 
Sodium  (Natronium) 
Strontium     .... 

Cobalt 

Copper 

Didymium 

Erbium  

•{Sulphur  

Fluorine  

Tantalum  

Glucinum  

or  Columbium  

Gold  (Auruni) 

Tellurium 

Hydrogen 

Terbium. 

Iodine  

Thallium  

Indium  

Thorium     

Iridium  

Tin  (Stannum)  

Iron  (Ferrum) 

Titanium  .. 

Lanthanum  . 

Tungsten  (Wolfram). 
Uranium  

Lead  (Plumbum)  

Lithium. 

1  Vanadium 

Magnesium 

Yttrium 

Manganese 

Zinc  .  . 

Mercury  (Hydrargyrum) 
Molybdenum 

Zirconium  

Nomenclature  of  Elements.  —  Many  elements  bear  in 
chemistry  the  same  names  as  in  common  language.  Ex. 
Zinc,  Sulphur,  Iron.  Others  are  named  from  some  striking 
peculiarity.  Ex.  Bromine  derives  its  name  from  a  Greek 
word  meaning  stench,  in  consequence  of  the  disgusting 
odor  it  evolves.  Others  from  the  place  or  substance  in 
which  they  were  discovered.  Ex.  Columbium,  because 


INORGANIC    CHEMISTRY.  12t 

it  was  found  in  an  American  mineral.  Tantalum  derives 
its  name  from  tantalite,  the  mineral  wherein  it  was  first 
found.  All  the  newly-discovered  metals  are  made  to  ter- 
minate in  urn  or  ium.  Ex.  Platinum,  Caesium,  Ruthe- 
nium. 

Symbols  of  Elements, — A  symbol  is  a  letter  or  combina- 
tion of  two  letters  used  to  indicate  one  equivalent  of  the 
element  for  which  it  stands.  We  have  therefore  a  symbol 
for  each  element,  as  0  for  Oxygen,  H  for  Hydrogen,  etc. 
The  symbol  is  either  the  first  letter  or  the  first  and  char- 
acteristic following  letter  in  the  name  of  the  element, 
as  will  be  seen  by  reference  to  the  above  table.  This 
second  letter  is  added  for  distinction  in  those  cases  where 
the  names  of  the  two  elements  commence  with  the  same 
letter.  Thus,  Carbon  and  Chlorine  both  commence  with 
the  letter  C.  In  order  to  distinguish  these  two  bodies,  we 
must  add  the  characteristic  letter  I  in  the  name  of  the 
body  last  discovered,  Chlorine,  to  its  first  letter  C,  so  as 
to  have  a  separate  symbol,  Cl,  for  Chlorine.  It  will  be 
noticed  that  the  second  letter  is  added  in  smaller  char- 
acter; and,  moreover,  the  definition  of  symbol,  given 
above,  makes  it  stand  for  only  one  equivalent  of  the  ele- 
ment. 0,  for  example,  does  not  represent  the  substance 
Oxygen  in  general,  but  merely  8  parts  by  weight  of  Oxy- 
gen. F  should  not  call  to  mind  Fluorine,  but  19  parts 
relatively  by  weight  of  Fluorine.  Since  a  symbol  stands 
for  one  equivalent  of  the  element,  we  must  place  figures 
if  we  wish  to  indicate  several  equivalents :  thus  the 
symbol  Au  stands  for  1  equivalent  of  gold.  To  represent 
5  equivalents  of  gold  we  write  5Au.  In  writing  the  for- 
mulae of  compound  bodies,  however,  the  figure  is  placed 
after  and  a  little  below  the  symbol :  thus  the  compound 
of  Nitrogen,  N,  with  5  equivalents  of  Oxygen,  50,  is  not 
represented  by  N50,  but  by  N05. 

2nd.    Binaries.  —  Binaries  are  compounds  of  two  ele- 


128  INORGANIC    CHEMISTRY. 

merits,  They  are  divided  into  three  orders :  I.  Acids ; 
II.  Bases;  and,  III.  Neutrals. 

An  Acid  is  a  body  having  a  sour  taste,  reddening  a  so- 
lution of  litmus,  or  of  violets  or  red  cabbage,  and  turning 
a  solution  of  cochineal  yellow,  and  combining  with  bases 
so  as  more  or  less  to  destroy  their  basic  properties  and  to 
form  with  them  salts. 

A  Base  is  a  body  having  a  peculiar  soapy  taste,  redden- 
ing a  solution  of  turmeric,  turning  one  of  violets  or  cab- 
bage green,  and  one  of  cochineal  purple ;  and  combining 
with  acids  to  form  salts,  with  mutual  neutralization  of 
properties. 

In  both  these  definitions  the  last  point  only  is  universal 
in  its  application.  Alkalies  are  strong  bases  which  fulfil 
all  the  conditions  above  expressed. 

A  Neutral  Body  is  one  so  devoid  of  all  active  properties 
that  it  can  scarcely  be  made  to  enter  into  combination.  It 
occupies  an  intermediate  position  between  acids  and  bases. 

I.  Acids  are  again  of  three  sorts,  (a)  Those  contain- 
ing Oxygen  or  Sulphur  in  union  with  a  metalloid  or 
metal,  as — 

Arsenious  acid  =  AsO,      Carbonic  acid  =    C02 


Sulpharsenious  acid    —  AsS3 


Sulphocarbonic  acid     =    CS2 


(6)  Those  containing  Sulphur,  Silenium,  or  Tellurium,  in 
union  with  Hydrogen,  (c)  Those  containing  Chlorine, 
Bromine,  Iodine,  Fluorine,  or  Cyanogen,  in  union  with 
Hydrogen. 

(a)  Acids  of  the  first  class,  which  contain  Sulphur,  are 
distinguished  from  those  containing  Oxygen,  by  prefixing 
sulph.or  sulpha  to  the  name  of  the  corresponding  oxygen 
acid ;  thus  AsS5  corresponds  to  As05,  Arsenic  Acid,  and 
accordingly  we  give  to  the  first  the  name  Sulpharsenic 
Acid. 

The  name  of  the  oxygen  acids  themselves  are  derived 
from  the  names  of  the  metalloids  or  metals  with  which 


INORGANIC    CHEMISTRY.  129 

the  Oxygen  is  combined.  Ex.  The  acid  body  formed  by 
the  union  of  Chlorine  with  Oxygen  takes  its  name  from 
the  metalloid,  and  is  called  Chloric  Acid. 

When  there  are  several  compounds  of  Oxygen  with  the 
same  element,  the  one  which  contains  the  most  Oxygen 
is  made  to  terminate  in  ic  ;  the  one  containing  the  least  in 
ous.  If  another  acid  is  afterwards  discovered,  containing 
more  Oxygen  than  the  acid  which  was  made  to  terminate 
in  ic,  hyper  (abbreviated  per}  is  prefixed  to  the  new  acid, 
to  distinguish  it  from  the  acid  first  discovered.  Hypo 
denotes  less  Oxygen  than  the  remainder  of  the  name  im- 
plies. The  above  rules  are  exemplified  in  the  following 
series  of  acids : — 


Perchloric  acid  —     C10r 

Hypochloric  acid       =      C104 


Chlorous  acid  =     C103 

Hypochlorous  acid     =     CIO 


Chloric  acid  =     C109 

(b  and  c)  The  names  of  acids  of  the  second  and  third 
class  are  formed  by  prefixing  hydro  to  the  name  of  the 
electro-negative  element. 


(6)  Hydrosulphuric  acid  —  HS 
Hydroselenic  acid       —  HSe 
Hydrotelluric  acid      =  HTe 


(c)  Hydrochloric  acid  =  HC1 
Hydrofluoric  acid  =  HF 
Hydrocyanic  acid  =  HCy 


And  it  will  be  noticed  that  the  symbol  likewise  of  the 
electro-negative  element  is  written  last  in  the  above  ex- 
amples. 

II.  Bases  are  named  from  both  elements  which  compose 
them,  the  more  electro-negative  being  named  first.  Ex. 
Oxygen  being  negative  to  iron,  these  when  united  form 
Oxide  of  Iron. 

In  writing  the  formulae  of  bodies,  however,  the  symbol 
of  the  electro-negative  is  placed  first.  Thus  we  express 
this  same  substance,  Oxide  of  Iron,  by  FeO. 

If  the  compound  contain  one  equivalent  of  the  electro- 
negative element  to  each  equivalent  of  the  electro-positive 


130  INORGANIC    CHEMISTRY. 

one,  prot  or  proto  is  prefixed  to  the  name  of  the  negative 
element;  if  2  equivalents  of  the  negative  to  each  of  the 
positive,  deut,  deuto,  bi,  or  bis  is  prefixed ;  if  3  negative  to 
2  positive,  sesqui;  if  3  negative  to  each  positive,  trit, 
trito,  or  ter ;  if  4  negative  to  each  positive,  quad  or 
quadro;  if  5  negative  to  each  positive,  pent  or  pent!.  Ex. 
FeO,  1:1;  Protoxide  of  Iron,  Fe02,  1:2;  Binoxide  of 
Iron,  Fe203,  2:3;  Sesquioxide  of  Iron,  Fe03,  1:3;  Ter- 
oxide  of  Iron. 

III.  Neutral  Bodies  are  of  two  kinds.  1st.  Those  formed 
by  the  union  of  a  halogen*  body  with  a  metal ;  they  are 
marked  by  peculiar  characteristics,  and  are  known  as 
Haloid  Salts.  2nd.  All  other  compounds  of  two  elements 
which  are  neither  acids  nor  bases.  Both  classes  are  named 
exactly  like  bases.  Ex.  NaCl,  Chloride  of  Sodium.  Mn02, 
Binoxide  of  Manganese. 

3rd.  Ternaries,  —  Consist  of  an  acid  and  a  base.  The 
negative  element,  in  both  acid  and  base,  must  be  the  same. 
Ex.  Arsenate  of  Potassa,  KO,As05.  Sulpharsenate  of 
sulphide  of  potassium,  KS,AsS5.  Every  such  union  of 
an  acid  with  a  base  is  called  a  Salt.  If  an  oxygen  acid  is 
united  with  an  oxygen  base,  we  have  an  Oxygen  Salt;  if 
a  sulphur  acid  with  a  sulphur  base,  a  Sulphur  Salt.  An 
oxygen  salt  is  named  by  giving  the  name  of  the  acid  first, 
with  its  termination  changed  from  ic  to  ate,  and  from  ous 
to  ite,  and  then  adding  the  name  of  the  positive  element 
in  the  base,  "oxide  of"  being  understood.  Ex.  Sulphate 
of  Iron,  FeO,S03.  A  sulphur  salt  is  named  in  the  same 
way,  but  "sulphide  of"  is  expressed.  If  the  acid  be  to 
the  base  in  the  ratio  of  1 : 1,  proto  is  prefixed  to  the  name 
of  the  salt ;  if  as  2:1,  bis  ;  if  as  3  :  2,  sesqui,  etc.  Salts 
are  divided  into  three  classes :  1st.  Acid  Salts.  2nd.  Neutral 
Salts.  3rd.  Basic  Salts.  See  page  It9. 

*  Halogen,  from  &\6g,  salt;  ytmzw,  I  produce.  They  are  Chlorine,  Bro- 
mine, Iodine,  Fluorine,  and  Cyanogen. 


OXYGEN.  131 

Sym.  0.  OXYGEN.  Eq.  8. 

Oxygen  was  discovered,  independently  of  each  other,  by 
Priestley  and  Scheele,  in  It 74.  It  was  called  by  Priestley 
" dephlogisticated  air,"  and  by  Scheele  "Empyrean  air." 
Its  true  nature  was  pointed  out  soon  after  by  Lavoisier, 
to  whom  it  owes  its  present  name  of  oxygen,  6|{>$  acid, 
yswdu,  I  produce.  Because  it  was  supposed  to  form  all 
acid  compounds.  This  idea  is  in  a  general  way  correct, 
but  by  no  means  universally  true.  Most  acids  contain 
0,  but  many  do  not. 

Sources  of  0.  —  Oxygen  constitutes  46  per  cent,  by 
weight  of  all  the  principal  rocks,  granite,  basalt,  gneiss, 
sandstone,  and  limestone  ;  30  per  cent,  of  all  the  common 
metallic  ores;  one-fifth  of  the  atmosphere,  and  eight- 
ninths  of  all  water. 

Preparation  of  0.  —  1st.  By  heating  Red  Oxide  of 
Mercury  to  750°  Fahr.,  HgO  =  Hg  -f  0.  This  process 
may  best  be  exhibited  by  placing  a  little  HgO  in  a  test 
tube,  supporting  this  in  the  retort  holder,  as  in  Fig.  124, 
and  heating  the  oxide  by  means  of  a  Bunsen  burner,  or 
powerful  Argand  lamp,  such  as  in  Fig.  125.  The  decom- 
position soon  begins.  Metallic  Mercury  is  deposited  in 
the  cooler  portion  of  the  tube,  and  the  escaping  gas  will 
relight  an  extinguished  match,  with  a  coal  yet  on  it,  if 
plunged  in  the  mouth  of  the  tube. 

2nd.  By  heating  to  redness  Black  Oxide  of  Manganese, 
Mn02  =  MnO  -f  Mn203  +  20.  This  requires  an  iron 
vessel  and  the  heat  of  a  good  fire. 

3rd.  By  heating  Chlorate  of  Potash  which  gives  off 
39  per  cent,  of  0,  KO,C105  =  KC1  +  60.  Half  an 
ounce  of  KOC105  yields  270  cubic  inches,  or  nearly  a 
gallon  of  0.  A  pound  yields  about  30  gallons. 

4th.  When  a  little  Black  Oxide  of  Manganese  is  mixed 
with  Chlorate  of  Potash,  the  Oxygen  is  disengaged  at  a 


132 


much  lower  temperature  than  otherwise.  The  Oxide  of 
Manganese  undergoes  no  change  and  seems  to  act  solely 
by  its  presence. 

The  operation  may  be  well  conducted  on  the  small 
scale  in  a  glass  flask  heated  by  a  spirit  lamp  with  an 
"Argand"  or  large  hollow  cylindrical  wick,  as  is  repre- 
sented in  Fig.  125,  the  gas  being  collected  as  it  forms,  in  a 
bell  jar  filled  with  air,  and  inserted  over  a.  pneumatic 
cistern.  An  India-rubber  tube  serves  best  to  convey  the 
gas  from  the  flask  to  the  cistern.  In  making  large  quan- 
tities of  oxygen  it  is  best  to  use  a  copper  flask  of  one  quart 
or  more  capacity,  heated  by  a  Bunsen  burner  which  should 
be  removed  as  soon  as  the  gas  begins  to  come  over  freely ; 
the  operation  will  then  continue  to  the  end  without  further 
heating.  The  gas  may  then  be  collected  in  a  gas  bag 
made  of  strong  India-rubber  cloth,  after  passing  through 


133 


a  large  washing  bottle,  or  in  such  a  receiver  as  is  shown 
in  Fig.  126,  or  Fig.  141. 

Fig.  126. 


To  use  the  gas  receiver,  Fig.  126,  we  fill  A  with  water 
by  pouring  it  into  B,  opening  the  stopcock  a  to  admit  it  to 
12 


134  OXYGEN. 

A,  and  the  cock  c  to  allow  the  air  to  escape.  Then  both 
these  cocks  being  closed,  we  remove  the  cork  from  d,  and 
pass  in,  through  this  passage,  the  tube  carrying  the  gas 
from  the  flask.  As  the  gas  enters  it  displaces  the  water, 
which  then  runs  out  around  the  entering  tube  at  d,  cc  are 
merely  iron  rods  supporting  B.  If  after  A  is  full  of  gas  d 
is  closed,  B  filled  with  water,  a  bell-jar  full  of  water  placed 
in  B,  and  the  cocks  a  and  b  opened,  water  will  flow  through 
a  into  A  and  drive  out  gas  through  b  into  the  bell  jar. 

5th.  By  strongly  heating  Ked  Lead,  2PbO,Pb02,  or 
almost  any  deutoxide  of  a  metal,  the  oxide  will  be  reduced 
to  a  protoxide,  yielding  oxygen. 

6th.  By  heating  Nitrate  of  Potash  (Nitre),  KON05  = 
KONOs+20. 

7th.  By  heating  a  mixture  of  2  parts  strong  Sulphuric 
acid  (oil  of  vitriol),  and  1  part  black  Oxide  of  Manganese, 
Mn02+SO=MnO,S03+0. 

8th.  By  heating  4  parts  of  Sulphuric  acid  with  3  parts 
of  Bichromate  of  Potash,  KO,Cr,06  -f  S03  =  KOS03-f 
Cr,033S034-30.  One  ounce  of  salt  yields  200  cubic 
inches  of  0. 

9th.  By  heating  Hydrated  Protoxide  of  Barium  in  alter- 
nate currents  of  air  and  steam,  when  it  will  take  0  from 
the  air  and  yield  it  to  the  steam. 

10th.  By  heating  Nitrate  of  Soda  and  Protoxide  of  Zinc. 
llth.  By  adding  to  Hypochloride  of  Lime  in  solution 
(obtained  by  mixing  commercial  bleaching  salt  or  chloride 
of  lime  with  water,  and  decanting  or  filtering  through  a 
cloth)  a  few  drops  of  nitrate  of  cobalt,  and  gently  heating. 
In  this  case  the  oxide  of  cobalt  which  is  formed,  abstracts 
oxygen  from  the  hypochlorous  acid  and  lime  (leaving  at 
last  but  chloride  of  calcium),  and  then  in  turn  abandons 
this  oxygen  only  to  seize  upon  a  fresh  quantity. 

A  pound  of  Chloride  of  Lime  (commercial)  treated  with 
about  a  quart  of  water  will  yield  in  this  way  2J  gallons 


OXYGEN.  135 

of  oxygen.  This  process  is  a  curious  one,  perfectly  safe 
and  easy  to  manage,  but  cumbrous  where  large  quantities 
of  gas  are  required,  and  no  cheaper  than  the  4th.  (See 
Journal  of  Franklin  Institute,  Vol.  50,  p.  285.) 

12th.  By  heating  together  Silica  (sand)  and  Sulphate  of 
Lime  (plaster  of  Paris),  Si02-f  CaO,S03=CaO,Si02+S02 
+  0.  Silicate  of  lime  is  formed,  and  Oxyger^with  Sul- 
phurous acid  passes  off.  The  S02  is  removed  by  lique- 
faction or  absorption  in  milk  of  lime,  and  the  0  thus 
obtained  pure. 

Of  all  these  methods  the  4th  is  at  present  the  most 
available. 

Properties. —  Oxygen  is  a  gas,  incapable  of  liquefaction 
by  cold  or  pressure,  and  without  color,  taste,  or  smell.  Its 
density  is  1.1057;  100  cubic  inches  at  60°,  and  29.988 
inches  barometric  pressure,  weighs  34.29  grains.  It  is 
slightly  soluble  in  water,  the  latter  dissolving  at  the  ordi- 
nary temperature  -j^  of  its  volume  of  gas.  It  is  the  most 
magnetic  of  gases  (see  p.  92) ;  in  this  respect  the  O  of 
the  atmosphere  is  equivalent  to  a  shell  of  iron  enveloping 
the  earth,  and  2|o  of  an  inch  thick ;  and  by  its  changes 
of  magnetism,  due  to  those  of  temperature,  produces  the 
diurnal  variations  of  the  magnet.  It  is  the  great  supporter 
of  combustion.  Almost  every  case  of  combustion  consists 
in  a  union  of  the  elements  of  the  burning  body  with  Oxy- 
gen. When  bodies  burn  in  the  air  the  great  excess  of 
nitrogen  present  carries  away  much  of  the  heat  generated, 
but  when  oxygen  alone  is  collected  in  a  receiver,  the  heat 
developed  by  combustion  can  rise  much  higher,  and  the 
more  ready  supply  of  the  "  supporting  body  "  will  greatly 
intensify  the  action. 

This  is  well  exhibited,  as  follows  : 
We  fill  bell-jars,  such  as  Fig.  127,  with  this  gas  over 
the  pneumatic  tank,  by  filling  them  first  with  water,  and 
then  allowing  the  gas  to  flow  into  them  from  a  tube  intro- 


136 


OZONE. 


Fig.  127. 


duced  under  their  immersed  lower  edge.  (See  Fig.  125.) 
We  then  attach  to  wires,  or  place  in  copper  spoons,  as 
their  nature  requires,  pieces  of  charcoal,  candle,  sulphur, 
phosphorus,  etc.  (dry  sand  should  be  placed  in  the  spoon, 
under  the  phosphorus),  and  ignit- 
ing, plunge  them  into  the  jars 
through  their  upper  openings. 
These  bodies  then  burn  with 
great  splendor. 

To  burn  iron,  or  rather  steel, 
we  use  an  uncoiled  watch-spring, 
which  can  be  best  ignited  by  the 
oxyhydrogen  blowTpipe,  and  then 
plunged  in  a  jar  of  oxygen,  or  we 
may  fuse  a  little  sulphur  fast  to  its  end,  light  this,  and 
then  plunge  it  into  the  gas. 

Figure  12f  represents  phosphorus  burning  in  oxygen; 
and  Fig.  128  steel,  in  like  case.  Ere- 
macausis  is  the  name  applied  to  a  very 
slow  combination  of  bodies  with  oxy- 
gen, by  which  no  light  is  evolved. 
This  we  see  in  decaying  wood,  and 
vegetable  matter  generally,  in  the  res- 
piratory process  of  animals,  etc.  Oxy- 
gen drawn  into  the  lungs  is  absorbed 
in  the  blood,  and  there  combines  with 
various  dead  matter,  exhausted  tissue, 
and  the  like,  so  producing  heat  needed  for  the  support  of 
animal  life. 

Ozone  and  Ant-Ozone, — Besides  its  usual  state,  Oxygen 
has  two  other  and  dissimilar  conditions  designated  by 
the  above  names. 

When  dry  air  or  oxygen  is  passed  through  a  glass  tube 
containing  a  number  of  fine  wires  coated  with  glass, 
which  form  the  poles  of  a  Ruhmkorff  Coil,  the  character 


Fig.  128. 


of  the  gas  is  changed.  If  it  is  passed  through  a  strong 
solution  of  Iodide  of  Potassium  (KI),  part  of  it  will  be 
absorbed,  setting  free  the  Iodine.  This  is  the  Ozone. 
Another  part  will  pass  on  unabsorbed,  and  may  be  col- 
lected with  the  gas  which  may  have  escaped  action  in  a 
dry  vessel. 

Its  chief  peculiarity  is  that  in  the  presence  of  moisture 
or  water,  it  forms  with  it  a  dense  white  cloud  or  fume, 
which  subsides 'after  half  an  hour  or  so,  leaving  the  water 
and  common  oxygen.  This  substance  so  acting  is  called 
Ant-ozone.  These  were  discovered  by  Schonbein,  and 
have  been  thoroughly  studied  by  Meissner.  (See  Silliman's 
Journal,  Yol.  31,  p.  325,  1864,  for  a  review  of  Meissner's 
book.) 

Ozone  is  prepared,  not  only  by  the  action  of  electricity 
on  air,  but  also  in  the  electric  decomposition  of  water 
(page  108) ;  by  the  action  of  phosphorus,  partly  covered 
with  water,  on  air ;  by  the  action  of  ether,  turpentine, 
etc.,  on  air;  by  action  of  oil  of  vitriol  on  chameleon 
mineral  (Silliman's  Journal,  1863,  Vol.  35,  p.  Ill);  and 
by  plunging  a  red-hot  glass  rod  into  a  glass  having  a  few 
drops  of  ether  in  it. 

Its  test  is  paper  moistened  with  starch,  containing  a 
little  KI  (starch,  5  parts  ;  Iodide  of  Potassium,  1  part ; 
to  be  boiled),  which  it  turns  purplish  blue,  or  the  juice  of 
mushroom,  Boletus  luridus,  Boletus  cyanescenus,  etc.,  or 
the  alcoholic  solution  of  the  resin  of  Guaiacum,  to  which 
it  communicates  a  blue  color. 

The  properties  of  ozone  are  like  those  ©f  oxygen,  but  in 
all  respects  more  intense.  It  has  a  peculiar  smell,  sug- 
gestive of  scratched  varnish,  which  may  be  easily  per- 
ceived in  the  vicinity  of  a  powerful  Ruhrnkorff  coil  or  elec- 
trical machine.  It  interferes  with  vegetation,  formation 
of  mould,  etc. 

Antozone  may  be  prepared,  not  only  in  the  way  above 


138 


HYDROGEN. 


described,  but  by  action  of  dilute  Sulphuric  acid  (S03)  on 
Deutoxide  of  Barium  (Ba02)  diffused  in  water  at  a  low 
temperature,  and  by  passing  Carbonic  acid  (CC^  through 
Ba02  diffused  in  water.  In  this  case,  however,  the  Anto- 
zone  at  once  unites  with  water  forming  H02.  Antozone 
again  seems  to  exist  in  Fluor  Spar  of  Welsendorf,  H02, 
being  formed  by  grinding  this  mineral  with  water. 

Test. — Antozone  will  develop  the  blue  purple  in  starch 
containing  KI,  if  very  dilute  solution  of  Sulphate  of  Iron 
(FeOS03)  be  first  added  to  that  mixture. 

Ozone  is  often  indicated  by  the  symbol  -f-  O,  and  Ant- 
ozone by  —  0,  and  these  are  sometimes  called  positive 
and  negative  oxygen. 


Sym.  H.  HYDROGEN.  Eq.  1. 

Hydrogen  was  discovered  by  Cavendish,  in  1T66.  its 
name  is  derived  from  vfiwp,  water ;  and  ycwaw,  I  produce. 
It  constitutes  one-ninth  of  all  water,  and  part  of  most 
animal  and  vegetable  bodies. 

Preparation. — We  always  obtain  H  from  water. 

1st.  By  decomposing  it  with  Sodium.  Invert  a  test 
tube  filled  with  water  in  a  dish  of  the  same,  introduce  a 
pellet  of  Sodium  (Na)  under  it  between  the  blades  of 


Fig.  129. 


Fig.  130. 


.A. 


;D 


scissors,  the  Na  will  soon  escape  and  float  on  the  water 


HYDROGEN 


139 


Fig.  131. 


in  the  tube,  setting  free  H,  which  will  thus  fill  the  latter. 
(Fig.  129.) 

2nd.  By  passing  steam  over  iron  filings  placed  in  a  tube 
and  kept  at  a  red  heat  by  a  furnace. 

3rd.  By  decomposing  water  acidulated  with  sulphuric 
acid  with  zinc  (HO,S03  -f  Zn  =  ZnO,S03  +  H.) 

This  operation  may  be  conducted  in  a  "gas  bottle," 
Fig.  130,  the  acid  and  water  (mixed  before  and  allowed 
to  cool)  being  introduced  by  the  long  funnel,  and  the  gas 
escaping  by  the  bent  tube.  Or  to  make  the  process  self- 
regulating,  we  may  employ  the  apparatus  represented  in 
Fig.  131,  where  the  gas,  generated  by  the  contact  of  the 
acid  water  with  the  zinc,  h, 
if  not  allowed  to  escape,  col- 
lects in  the  bell  jar,  displacing 
the  acid  solution  from  the 
zinc,  and  so  stops  the  action 
until  the  gas  is  allowed  to 
escape,  admitting  the  liquid 
when  the  operation  recom- 
mences. Such  an  apparatus, 
made  of  copper  and  of  large 
size,  is  very  convenient  to 
work  the  oxy hydrogen  blow- 
pipe, lime-light,  etc.  The 
bell  in  this  case  had  better 
float  loose  in  the  outer  jar  or 
reservoir,  and  have  a  capa- 
city of  6  gallons.  The  charge 
should  be  a  bucket  of  water 
which  will  yield  more  than  70  gallons  of  Hydrogen. 
Enough  to  run  a  powerful  lime-light  for  two  hours. 

4th.  By  electrical  decomposition  of  water  (see  page  108). 
When  prepared  by  this  means,  the  hydrogen  has  its  affini- 
ties exalted  so  that  it  will  decompose  Sulphate  of  silver. 
(Smithsonian  Reports,  1862,  p.  397.) 


and  6  Ibs.  of  oil  of  vitriol, 


140  HYDROGEN. 

Properties. —  Hydrogen  is  a  gas,  colorless,  transparent, 
tasteless,  and  inodorous ;  it  has  a  higher  refractive  power 
than  any  other  gas ;  it  is  the  lightest  known  substance,  weigh- 
ing little  more  than  yL  as  much  as  air.  Density,  0.0692. 
One  hundred  cubic  inches  weigh  2.14  grains.  On  account 
of  its  lightness  balloons  have  been  filled  with  it,  and  soap 
bubbles  so  charged  rise  in  the  air.  It  may  be  collected 
by  displacement  (see  Fig.  130),  and  poured  upwards  from 
one  vessel  into  another. 

The  extreme  rarity  of  hydrogen  was  strikingly  demon- 
strated in  the  attempts  which  were  made  to  condense  it 
to  a  liquid,  by  great  pressure  in  iron  receivers.  The  hy- 
drogen escaped  through  the  pores  of  the  iron.  Ex.  If  a 
sheet  of  paper  is  placed  at  a  little  distance  from  the  jet  of 
a  hydrogen  generator,  the  current  of  gas  will  pass  directly 
through  the  paper  without  altering  its  direction,  and  can 
be  lighted  upon  the  opposite  side  of  the  sheet. 

Hydrogen  is  combustible,  burning  with  a  bluish  flame, 
giving  little  light  but  intense  heat.  If  a  long  glass,  or 
other  tube,  is  placed  around  a  small  jet  from  which  H.  is 
burning,  the  supply  of  air  being  thus  limited  the  burning 
will  be  reduced  to  a  series  of  slight  explosions,  which  will 
develop  a  musical  sound.  This  arrangement  has,  there- 
fore, been  called  the  HYDROGEN  ORGAN. 

The  Oxyhydrogen  Blowpipe,  invented  by  Dr.  Robert 
Hare,  in  1802,  consists  of  two  concentric  nozzles  with 
other  parts,  by  which  a  jet  of  oxygen  is  introduced  into 
the  centre  of  a  jet  of  burning  hydrogen.  The  most  com- 
bustible body  is  thus  supplied  with  the  best  supporter  of 
combustion,  and  the  heat  evolved  by  their  union  is  con- 
centrated in  a  small  space.  Its  intensity  is  therefore  very 
great.  Silver,  gold,  platinum,  etc.,  are  fused  and  vapor- 
ized. -Iron,  zinc,  etc.,  burned  with  brilliant  effect,  and 
other  results  of  a  high  temperature  attained. 

The  Lime-light.  —  When  the  oxy hydrogen  flame  is  di- 


HYDROGEN.  141 

rected  upon  a  block  of  lime,  this  solid  serves  as  a  sounding- 
board  to  its  intense  vibrations  ;  and  enables  them  thus  to 
develop  a  light  of  great  brilliancy.  For  the  best  effect, 
the  pressure  on  the  gases  should  not  be  less  than  f  Ib. 
per  square  inch,  or  18  inches  on  a  water  gauge.  If  these 
two  gases,  0  and  H,  are  mingled  in  atomic  proportions 
(by  volume,  1  to  2 ;  by  weight,  8  to  1)  and  ignited,  they 
will  explode  with  violent  detonation,  though  relatively 
little  force.  This  is  well  shown  by  blowing  bubbles  in 
soapy  water  with  the  mixed  gases  (from  a  bladder,  gas- 
bag, or  other  receptacle),  filling  the  hand  with  these  and 
firing  them.  They  will  make  a  loud  report,  but  will  pro- 
duce no  sensation  to  the  hand.  The  detonation  is  caused 
by  the  instantaneous  condensation  of  the  vapor  of  water, 
which  is  produced  by  the  combination  of  the  two  gases  in 
contact  with  cold  air.  The  water  occupying,  when  con- 
densed, a  volume  1700  times  smaller  than  when  it  was  in 
the  state  of  vapor,  leaves  a  large  vacuum.  The  rushing 
of  the  air  from  every  quarter  with  great  rapidity  into  this 
empty  space,  causes  the  detonation. 

Compounds  of  Hydrogen  with  Oxygen. 

I.  Water.— Symbol,  HO.  Equivalent,  9.  Sp.  Gr.  as 
Yapor,  0.622;  as  Liquid,  1.000;  as  Ice,  0.94. 

Properties,  (a)  Physical. — Clear,  colorless,  tasteless,  in- 
odorous, transparent  liquid.  Below  32°  it  freezes  into  a 
variety  of  crystalline  forms  derived  from  the  rhombohe- 
dron  and  six-sided  prism.  Evaporates  at  all  temperatures, 
and  under  the  usual  pressure  of  the  atmosphere  boils  at 
212°  Reaches  its  maximum  density  at  about  40°,  and 
expands  whether  cooled  below,  or  heated  above,  this  point. 
In  changing  to  ice,  it  becomes  lighter  and  increases  in 
volume  ;  and  we  therefore  see  why  : 

1st.  Ice  forms  only  on  the  top  of  streams.  If  water 
followed  the  same  law  as  almost  all  other  liquids,  and 


142  HYDROGEN. 

became  heavier  in  freezing,  our  rivers  would  be  frozen 
solid  from  bed  to  surface,  the  fish  they  contained  destroyed, 
navigation  would  be  interrupted  for  most  of  the  year,  and 
all  the  heat  of  a  summer  sun  would  scarcely  suffice  to 
make  the  streams  liquid  again. 

2nd.  A  frost,  by  changing  the  water  contained  in  the 
cellular  tissue  of  fruit  to  ice,  bursts  the  delicate  cell  struc- 
ture and  destroys  the  fruit. 

3rd.  Water  pitchers,  fountains,  water-pipes,  drains,  etc., 
burst  in  winter  time,  and  frost-stones,  or  those  very  porous 
to  water,  crumble  away. 

Its  density  at  60°  is  taken  as  1.000;  and  with  this 
standard  the  specific  gravities  of  all  liquids  and  solids  are 
compared.  One  cubic  inch  of  water  at  62°,  weighs  252.456 
grains.  A  gallon  (imperial)  contains  10  Ibs.  Avoirdu- 
pois =  70.000  grains,  or  277.19  cubic  inches  of  water. 

Air  dissolved  in  Water. — The  presence  of  air  in  water 
which  has  been  exposed  to  the  atmosphere,  is  readily  shown 
by  suffering  some  water  to  stand  for  a  time  in  a  quiet 
tumbler.  Bubbles  of  gas  collect  on  the  inside  of  the 
glass;  accurately,  the  amount  of  air  is  about  3.2  volumes 
to  every  100  volumes  of  water.  But  this  dissolved  air 
is  much  richer  in  oxygen  than  atmospheric  air,  and  con- 
tains 33  volumes  of  oxygen  to  100,  instead  of  the  21 
volumes  which  are  found  in  the  atmosphere.  This  excess 
of  oxygen  is  due  to  its  being  more  soluble  in  water  than 
nitrogen.  Ex.  Fishes,  which  breathe  the  air  dissolved  in 
water  by  means  of  their  gills,  die  in  distilled  water.  Spring 
waters  derive  their  sparkling  taste  and  invigorating  quali- 
ties from  the  air  which  they  hold  in  solution. 

Other  bodies  found  in  water. — Rain-water,  in  its  pas- 
sage from  the  clouds,  carries  with  it,  in  solution,  all  the 
substances  which  are  found  in  the  atmosphere ;  such  as 
oxygen,  nitrogen,  carbonic  acid,  traces  of  nitric  acid,  of 
carbona.te  and  nitrate  of  ammonia. 


NITROGEN.  143 

Spring  and  well  water,  which  is  rain-water  drained  from 
porous  soils  or  rocks,  contains,  in  addition  to  the  above 
substances,  various  salts  which  it  has  dissolved  out  from 
the  ground ;  such  as  chlorides,  sulphates,  and  carbonates 
of  lime,  magnesia,  soda,  potassa,  and  alumina.  A  small 
quantity  of  lime-salts  is  thought  to  render  drinking-water 
more  healthy,  and  to  aid  in  building  up  the  bony  structure 
of  the  body. 

(6)  Chemical. — Is  the  best  solvent.  Perfectly  neutral ; 
uniting  with  most  acids  and  bases.  When  combined  with 
a  powerful  acid,  it  supplies  the  place  of  a  base,  and  is 
called  basic  water.  In  combination  with  a  powerful  base, 
it  supplies  the  place  of  an  acid,  and  is  called  acid  water. 
Bodies  combined  with  water  are  termed  hydrates-,  un- 
combined,  anhydrous.  If  the  water  existing  in  a  crys- 
tallized salt  can  be  driven  off  by  heat  without  decompos- 
ing the  salt,  it  is  termed  water  of  crystallization;  if  it 
cannot,  water  of  constitution. 

II.  Binoxyde  of  Hydrogen— H02= 17.    Sp.  Gr.  1.453. 

Preparation. — Successive  portions  of  Binoxide  of  Ba- 
rium are  added  to  Hydrofluoric  acid.  Ba02+HF=BaF 
-fHO2.  The  insoluble  Fluoride  of  Barium  is  removed  by 
filtration,  and  the  Binoxide  of  Barium  remaining  in  the 
liquid,  concentrated  by  evaporation  in  vacuo. 

Properties. — A  syrupy,  colorless  liquid,  with  an  astring- 
ent and  somewhat  metallic  taste ;  bleaching  litmus  and 
other  vegetable  colors  instantly.  At  79°  slowly  decom- 
posed into  oxygen  and  water  ;  at  212°,  with  explosive 
haste.  Many  metals  and  metallic  oxides  instantly  effect  a 
like  decomposition  without  themselves  undergoing  change. 

Sym.  N.  NITROGEN.  Ex.  14 

Discovered  by  Dr.  Rutherford,  in  1772.     Shown  to  form 

part  of  atmosphere  by  Lavoisier,  in  1175.     Called  by  the 

French  azote  (lifeless);  from  a,  privative,  and  £W ,  life.    Its 


144  NITROGEN. 

name,  nitrogen,  is  from  wVpov,  nitre,  and  ytvi/aw,  I  produce. 
Occurs  as  four-fifths  of  the  atmosphere,  and  in  mineral  and 
animal  substances. 

Preparation.  —  1st.  By  burning  phosphorus  in  an  in- 
closed portion  of  air  over  wat£r.  N  and  5  0  +  P  =  1ST  -f 
P05.  2d.  By  passing  chlorine  through  aqua  ammoniae. 
NH3+  3  Cl  =  3  HC1  -f  N.  3rd.  By  heating  solution  of 
nitrite  of  ammonia  NH40,N03  =  4  HO  +  2  N.  4th.  By 
heating  solution  of  nitrite  of  potassa  with  sal  ammoniac. 
KO,N03  +  NH4C1  =  KC1  +  4  HO  +  2  N. 

Properties.  —  These  are  all  inert  and  negative.  A  gas 
without  color,  taste,  smell,  or  capability  of  liquefaction, 
and  solidifaction ;  density  0.972  ;  does  not  support  combus- 
tion, animal  life,  or  enter,  of  its  own  accord,  into  combi- 
nation. Its  use  as  a  constituent  of  the  air,  seems  merely 
to  dilute  the  oxygen. 

Mixture  of  Nitrogen  with  Oxygen. 

Atmospheric  Air.  —  Density  at  60°  taken  as  1.000,  and 
with  this  standard  the  specific  gravities  of  all  other  gases 
are  compared;  100  cubic  inches  weigh  31.0111  grains. 
Consists,  by  weight,  of  23  parts  oxygen,  and  77  parts 
nitrogen;  by  measure,  of  21  parts  oxygen,  to  79  parts 
nitrogen.  There  is  also  about  one-thousandth  part  of 
carbonic  acid  gas,  a  trace  of  ammonia,  and  some  vapor, 
varying  greatly  in  quantity  with  the  temperature. 

Regnault's  Hygrometer.  —  The  amount  of  moisture  in 
the  air,  of  course,  affects  its  power  of  taking  more,  or  of 
promoting  evaporation.  The  dryer  the  air,  the  more 
rapid  will  be  the  evaporation  taking  place  in  it  at  equal 
temperatures.  We.  can  thus  determine  the  amount  of 
moisture  in  the  air  by  means  of  this  action,  as  follows. 
We  have  two  thermometers  (t  f),  supported  near  each 
other,  one,  however,  plunged  in  a  vessel  of  ether,  A. 
through  which  air  is  drawn,  by  means  of  the  aspirator, 


NITROGEN. 


145 


D.  The  dryer  the  air,  the  more  the  ether  evaporates, 
and,  therefore  (see  p.  32),  the  lower  the  temperature  in 
A  (indicated  by  one  thermometer)  falls  below  that  of  the 
air  around  indicated  by  the  other.  This  difference  in 
temperatures  enables  us  to  judge  of  the  amount  of  mois- 
ture in  the  air. 


Fig.  132. 


The  aspirator,  D,  is  used  in  many  cases  where  we  wish 
to  produce  a  steady  flow  of  air  through  a  piece  of  appa- 
ratus, as  in  some  cases  of  analysis,  the  determination  of 
the  Carbonic  acid  in  the  air,  etc. 
13 


146 


NITROGEN. 


Fig.  133. 


The  Dew  Point  is  that  temperature  at  which  the  mois- 
ture present  in  the  air  is  enough  to 
saturate  it,  and  would  begin  to  be 
deposited  from  it  as  dew.  This  is 
directly  shown  by  Daniel's  Hy- 
grometer. (Fig.  133.)  This  con- 
sists of  a  little  cryopherous  (see  page 
31),  with  a  thermometer  in  one  bulb, 
a,  and  a  piece  of  cloth  around  the 
other,  b.  By  pouring  ether  over  b, 
we  so  promote  evaporation  in  a,  that 
its  surface  is  cooled  to  the  dew  point^ 
and  we  see  a  misty  deposit  forming 
on  a,  which  is  coated  with  gold  leaf, 
to  show  this  the  better.  The 
temperature  of  the  thermometer 

in  a,  at  the  time  this  happens,  gives  us  the  dew  point. 

This  temperature  is  "  high,"  or  near  that  of  the  air,  in 

damp  weather;  "low,"  or  much  below  it,  when  the  air 

is  dry. 

Compounds  with  Oxygen, 

Nitrous  Oxide,  Protoxide  of  Nitrogen,  Laughing  Gas 
(NO ;  Eq.  22).  Sp.  Gr.  1.525.  Colorless,  transparent, 
sweet  tasting  gas ;  liquefiable  at  45°  under  a  pressure 
of  50  atmospheres ;  a  candle  or  phosphorus  burns  fiercely, 
when  plunged  in  this  gas.  Its  solubility  diminishes 
rapidly  with  increase  of  temperature ;  100  cubic  inches 
of  water,  at  32°,  dissolving  130  cubic  inches  of  the  gas; 
and  at  75°,  only  60  cubic  inches.  It  intoxicates  when 
inhaled,  and  produces  insensibility  to  pain.  Prepared  by 
heating  nitrate  of  ammoniae,  NH40,N05  =  4  HO  -f  2  NO. 

Nitric  Oxide,  Binoxide  of  Nitrogen,  NO2.  Obtained  by 
acting  upon  copper,  with  dilute  Nitric  acid.  3  Cu  -f 
4  N05  =  3  (CuO,N05)  -f  N02.  Colorless ;  in  contact  with 


NITROGEN. 


147 


air  or  oxygen  is  converted  into  a  deep-red  gas,  which  is 
the  vapor  of  hyponitric  acid,  NO*  =  N02  +  20.  Ex- 
tinguishes a  candle,  but  causes  phosphorus  to  burn 
brilliantly. 

Nitrous  Acid  —  N03.  An  orange-red  vapor,  obtained  by 
mixing  4  volumes  binoxide  of  nitrogen,  with  one  volume 
oxygen.  N02  +  0  =  N03.  In  contact  with  water,  de- 
composed into  Nitric  acid,  and  Binoxide  of  Nitrogen, 
2HO  +  6NO2  =  2  (HO,  N05)  +  4N02.  On  account  of 
a  like  action,  it  cannot  be  made  to  unite  directly  with 
metallic  oxides  ;  the  various  nitrites  are  formed  by  heating 
corresponding  nitrates  ;  thus,  KO,N05  =  KO,N03  -f  20, 
oxygen  being  evolved. 

Hyponitric  Acid  —  NO4.  A  deep  red  vapor,  at  common 
temperatures,  at  0°,  an  orange  liquid  ;  obtained  by  heat- 
ing nitrate  of  lead.  PbO,  NO5  =  PbO  +  0  +  NO4. 

Nitric  Acid  —  NO5.  A  crystalline  solid,  obtained  by  pass- 
ing dry  Chlorine  overwell  dried  Nitrate  of  Silver^gO,N05 


Fig.  134. 


Hydrated  Nitric  Acid—  HO,N05.  The  Hydrated  acid  is 
always  meant  when  Nitric  acid  is  spoken  of,  because  An- 
hydrous Nitric  acid  is  utterly  devoid  of  acid  properties. 
It  is  obtained  by  heating  equal  weights  of  Nitrate  of  Po- 
tassa  and  Sulphuric  acid,  KO,NO5+2(HO,S03)  =KO,S03 
+  HO,S03HO,N05. 

We  place,  for  ex- 
ample, the  above 
materials  in  a  glass 
retort,  Fig.  134, 
and  apply  heat  by 
means  of  a  spirit 
lamp  ;  then,  as  the 
Hydrated  Nitric 
acid  is  liberated,  it 
distils  over  into 


148  NITROGEN. 

the  glass  receiver,  kept  cool  by  a  stream   of  water  dis- 
tributed on  its  surface  by  means  of  linen  or  soft  paper. 

Besides  this  compound,  which  has  a  specific  gravity 
of  1.517,  and  which  consists  of  54  parts  Anhydrous  acid 
united  with  9  parts  water;  another  definite  compound 
of  the  Anhydrous  acid  with  water  exists,  which  has  a  spe- 
cific gravity  of  1.424,  and  contains  54  parts  of  the  former 
to  36  parts  of  the  latter.  Its  formula  would,  therefore,  be 
4HO,N05. 

Properties.  —  The  metals  placed  in  contact  with  Nitric 
acid  are  oxidized  at  the  expense  of  the  acid,  the  latter  easily 
yielding  up  a  portion  of  its  oxygen  to  them  ;  and  owing  to 
this  free  liberation  of  oxygen  combustible  bodies,  such  as 
charcoal  powder,  oil  of  turpentine,  sulphur  and  phosphorus, 
burn  vividly  when  Nitric  acid  is  dropped  upon  them.  Its 
chief  use,  indeed,  is  as  an  oxidizing  agent.  Strangely 
enough,  when  diluted  till  its  specific  gravity  is  1-25,  it  oxi- 
dizes the^metals  more  rapidly  than  when  concentrated. 
And  the  same  is  true  with  regard  to  its  action  upon  animal 
and  vegetable  bodies,  such  as  the  skin,  wool,  feathers,  and 
albuminous  bodies,  lignin,  starch,  and  similar  substances. 

Uses.  —  Owing  to  the  rapidity  with  which  Nitric  acid 
oxidizes  the  metals,  and  the  great  solubility  of  the  nitrates 
in  water,  Nitric  acid  is  of  invaluable  use  in  the  laboratory 
for  dissolving  minerals,  metals,  etc.  Used  to  oxidize  SO-2 
into  S03  in  the  manufacture  of  sulphuric  acid  ;  when  mixed 
with  hydrochloric  acid,  as  aqua  regia,  to  dissolve  gold, 
platinum,  etc. ;  to  convert  starch  and  sugar  into  oxalic 
acid;  in  dyeing ;  in  engraving  on  copper  and  steel — etch- 
ing; in  the  assay  of  money ;  in  polishing  and  cleaning 
rust  from  metals  and  alloys.  It  converts  benzole  into  arti- 
ficial oil  of  bitter  almonds;  it  is  employed  in  forming  ani- 
line colors,  and  to  transform  cotton  fibre  to  gun-cotton. 

Tests. — Bleaches  a  solution  of  Indigo  in  Sulphuric  acid 
when  boiled  with  that  liquid.  Gives  a  brownish-red  color 


AMMONIA.  149 

in  contact  with  a  concentrated  solution  of  Protosulphate 
of  Iron. 

Compounds  of  Nitrogen  and  Hydrogen. 
Sym,  NH3.       AMMONIA  (Volatile  Alkali).  Eq.  17. 

Sources. — When  Nitrogen  and  Hydrogen  come  together 
in  the  nascent  state,  that  is,  at  the  moment  when  either 
one  of  them  is  liberated  from  some  previous  combination, 
they  unite  to  form  Ammonia.  Thus,  when  lightning  flashes 
through  the  air  a  small  amount  of  vapor  of  water,  HO,  is 
decomposed  into  its  two  component  elements,  H  and  0. 
The  hydrogen  and  oxygen,  at  the  moment  of  their  libera- 
tion, unite  with  the  nitrogen  of  the  atmosphere  ;  the  former 
to  form  Ammonia.  NH3 ;  the  latter,  Nitric  acid,  N05.  Or, 
when  iron  is  exposed  to  the  action  of  moist  air,  the  iron 
decomposes  the  water,  and  unites  with  its  oxygen,  to  form 
rust  or  Sesquioxide  of  iron  (Fe203),  while  the  Hydrogen  set 
free,  in  the  nascent  state,  combines  with  the  nitrogen  of 
the  air  to  form  Ammonia:  2Fe  +  3HO  +  N=Fe203-fNH3. 
Ex.  Disengagement  of  Ammonia  from  rust  on  mixing  the 
latter  with  caustic  potash. 

In  the  same  manner,  when  Nitric  acid  acts  upon  zinc, 
tin,  and  iron  ;  thus,  8Zn-f-8(HO,N05)=8(ZnO,N05)  +  8H, 
the  liberated  hydrogen  has  the  power,  while  in  the  nascent 
state,  to  decompose  another  portion  of  the  Nitric  acid,  and 
form  Ammonia:  HO,N054-8Hr=6HO  +  NH3. 

Lastly,  when  organic  substances  decompose  —  I.  Spon- 
taneously—  II.  By  heat  alone  —  III.  By  heating  with 
caustic  potassa  —  the  nitrogen  and  hydrogen  combine,  in 
the  nascent  state,  to  form  Ammonia,  and  in  this  way  is 
derived  the  fertilizing  property  of  manure,  and  the  am- 
moniacal  liquor  of  gas-works,  which  is  the  commercial 
source  of  Ammonia. 

Preparation. — I.  Fill  a  matrass  half  full  of  equal  weight 
13* 


150 


AMMONIA. 


of  caustic  potash  and  sal  ammoniac,  and  heat  the  mixture 
gently  ;  collect  over  mercury,  or  by  displacement  upwards : 

Potassa.    Chloride  of  Ammonium.    Chloride  of  Calcium.     Ammonium.        "Water. 


KO,HO+ 


=        KC1 


2HO 


Fig.  135. 


II.  A  slight  heat  is  sufficient  to  disengage  all  the  Am- 
monia from  its  solution  in  water — the  liquid  Ammonia  of 
commerce. 

Liquid  Ammonia  is  prepared  by  receiving  the  ammo- 
niacal  gas,  first  in  a  wash-bottle,  filled  with 
milk  of  lime,  which  is  merely  the  hydrate 
of  lime,  HO,CaO,  diffused  through  water, 
in  order  to  absorb  the  Carbonic  acid  and  im- 
purities accidentally  present,  and  afterwards 
in  a  series  of  Woulf's  bottles,  Fig.  135,  filled 
with  distilled  water.  The  gas  enters  by 
tube  A,  bubbles  through  the  water,  and 
passes  by  C  into  another  similar  bottle. 
The  tube  D  serves  to  prevent  the  liquid  in 
one  bottle  from  being  drawn  into  another  in  case  of  a  sud- 
den absorption,  air  instead  then  entering  by  this  tube. 

Properties. — Ammonia  is  a  colorless  gas,  which  may  be 
recognized:  1st,  by  its  sharp,  penetrating  odor;  2nd,  by 
its  power  of  bluing  turmeric  paper,  turning  a  solution  of 
violets  green,  and  cochineal,  purple  —  whence  its  name  of 
volatile  alkali;  3rd,  by  the  white  fumes  or  cloud  of  Chlo- 
ride of  Ammonium,  NH4C1,  which  revolve  about  a  glass 
rod  previously  moistened  with  Hydrochloric  acid,  HC1, 
when  brought  near  the  slightest  trace  of  free  ammonia. 
It  extinguishes  a  burning  candle,  but  burns  with  a  yellow 
flame  when  introduced  in  a  fine  jet  into  a  bell-glass  filled 
with  oxygen  ;  it  cannot  be  respired,  and  produces  ophthal- 
mia among  workmen  exposed  to  ammoniacal  fumes. 
Dropped  on  the  skin,  liquid  ammonia  produces  a  blister, 


CHLORINE.  151 

and  it  is  consequently  employed  to  cauterize  the  bites  of 
mad  dogs.  It  is  decomposed  by  heat  and  electricity  into 
nitrogen  and  hydrogen ;  by  oxygen,  with  the  aid  of  elec- 
tricity, into  water  and  nitrogen  ;  a  few  bubbles  of  chlorine 
passed  into  a  receiver  filled  with  ammoniacal  gas  produce 
chloride  of  ammonium  and  nitrogen,  accompanied  by  heat 
and  light. 

Uses. — Equal  amounts  of  cochineal,  ammonia,  and  water 
boiled  together  furnish  carmine.  Many  colors  may  be 
made,  and  still  others,  such  as  crimson  and  Prussian  blue, 
may  be  modified  by  ammonia.  It  is  largely  employed  by 
scourers  to  take  out  grease  spots,  and  to  restore  colors 
changed  by  acids  ;  by  the  manufacturers  of  artificial  pearls 
to  prepare  the  Essence  d1  Orient.  This  is  obtained  by  hold- 
ing in  suspension  in  liquid  Ammonia  the  minute  scales  of 
the  Blay-fish,  and  is  used  by  injecting  it  into  pearl-like  glo- 
bules of  glass.  The  scales  attach  themselves  to  the  inside 
walls  of  the  hollow  glass  drops,  and  sparkle  like  Indian 
pearls. 

In  medicine,  besides  its  internal  and  external  application 
to  the  bites  of  serpents,  stings  of  insects,  etc.,  it  is  used  in 
the  treatment  of  hoven.  This  disease  arises  in  sheep  and 
cows  from  eating  green  apples  and  wet  grass,  which  gene- 
rate so  large  a  quantity  of  Carbonic  acid  in  the  intestines, 
as  to  cause  death  in  a  short  time.  The  ammonia  absorbs 
this  gas,  forming  the  salt,  Carbonate  of  Ammonia. 


Sym.  01.  CHLORINE.  Eq.  35.5. 

Discovered  by  Scheele  in  1144.  Its  true  character  pointed 
out  by  Gay  Lussac  and  Thenard  in  1809.  Its  name  given 
by  Sir  H.  Davy,  from  a^wpoj,  yellowish-green,  color  of 
young  grass.  Chief  source  in  nature,  common  salt. 

Preparation.  —  1st.  Heating  in  a  flask  slightly  diluted 
hydrochloric  acid  with  binoxide  of  manganese,  2HC1+ 


152 


CHLORINE. 


Mn02=MnCl  + 


(Fig.  136);  2nd.  Heating  com- 


mon  Salt,  Binoxide  of  Manganese  and  Sulphuric  acid, 
NaCl  +  Mn02  +  2(HO,S03)=Cl  +  NaO,S03-f  MnO,SO3  + 
2HO.  Best  collected  by  displacement,  as  Fig.  136,  or  if 

Fig.  136. 


for  any  reason  over  water  cold  water  is  better  than  hot, 
care  being  taken  to  let  it  pass  through  as  little  as  possible. 

Properties.  —  Chlorine  is  a  gas  of  a  greenish-yellow 
color,  an  acrid  taste  and  disgusting  suffocating  smell.  It 
becomes  liquid  under  a  pressure  of  4'5  atmospheres  at  60°. 

This  gas  has  a  strong  affinity  for  the  metals,  so  that 
many  of  them  will  inflame  if  thrown  into  it.  Thus,  for 
example,  is  it  with  Antimony,  Arsenic,  Potassium,  etc., 
in  powder,  or  Dutch  gold  leaf  (made  of  brass).  (Fig.  137.) 
Its  affinity  for  Hydrogen  is  also  very  great ;  mingled  with 
that  body  it  will  combine  slowly  in  diffused  light,  but  ex- 
plosively in  the  direct  rays  of  the  sun,  electric  lamp,  etc. 
To  this  attraction  it  owes  its  efficiency  as  a  bleaching 
agent.  .  By  combining  with  and  removing  the  Hydrogen 
from  organic  coloring  matter  it  destroys  it,  and  thus 
bleaches  or  removes  all  such  substances. 


CHLORINE. 


153 


Fig.  137. 


Bleaching.  —  In  practice,  goods  to  be  bleached  are  first 
well  washed  and  boiled  in  water  with  strong  alkalies, 
to  remove  all  grease,  etc. ;  then  they 
are  saturated  with  chloride  of  lime 
mixed  in  water;  then  they  are  im- 
mersed in  water  containing  a  little 
sulphuric  acid,  which  liberates  chlo- 
rine from  the  chloride  of  lime  con- 
tained in  the  cloth  among  its  fibres. 
This  effects  the  bleaching  most  per- 
fectly. The  cloths  must  lastly  be 
washed  for  a  long  time  in  fresh  water, 
to  remove  all  trace  of  acid.  To  re- 
move stains  from  linen  or  cotton  goods, 
in  the  small  way,  Chloride  of  Soda 
(Labarraque's  Solution)  or  Chloride 
of  Potash  (Javelle  water)  which  may 
be  obtained  from  any  apothecary,  are 
very  useful.  The  stained  cloth  should 
be  immersed  in  the  solution ;  a  little 
boiling  water  added,  if  necessary,  or, 
in  obstinate  cases,  the  whole  placed  in 
the  sun  for  some  hours.  The  article 
should  be  thoroughly  rinsed  with  fresh 
water  before  it  is  allowed  to  dry.  Col- 
ored fabrics  cannot  be  thus  treated,  as  their  color  would 
disappear  with  the  stain. 

Woollen  cloths  are  not  bleached  with  chlorine,  but  with 
fumes  of  burning  sulphur,  i.  e.  Sulphurous  acid,  S02. 

It  is  by  an  action  similar  to  the  above  that  Chlorine 
acts  as  a  deodorizer,  breaking  up  the  offensive  gases  by 
removing  their  hydrogen  or  like  element.  A  little  chlo- 
ride of  lime  thrown  under  a  floor  will  thus  afford  entire 
relief  from  the  "  attacks"  of  a  dead  mouse. 

Test — We  recognize  free  Chlorine  by  its  smell,  color, 


154  CHLORINE. 

heavy  fume  with  ammonia,  curdy  white  precipitate  with 
nitrate  of  silver,  and  bleaching  of  organic  colors. 

Compounds  of  Chlorine  and  Oxygen. 

Hypochlorous  Acid — CIO.  An  orange-yellow  liquid,  ob- 
tained by  passing  Chlorine  over  red  Oxide  of  Mercury, 
2HgO  -f  2C1  =  HgCl,HgO  +  CIO.  Readily  decomposed 
by  heat  into  oxygen  and  chlorine.  It  bleaches  powerfully, 
and  combines  with  the  alkalies  to  form  hypochlorites,  pos- 
sessing the  same  property. 

Chlorous  Acid — C102.  A  greenish-yellow  gas,  obtained 
by  heating  a  mixture  of  Arsenious  acid,  Chlorate  of  Po- 
tassa,  and  Nitric  acid.  The  nitric  acid  yields  up  some  of  its 
oxygen  to  the  arsenious  acid ;  nitrous  acid  is  formed,  and 
afterwards  converted  back  again  into  nitric  acid  by  oxygen 
given  off  from  the  decomposed  chloric  acid.  Thus  As03 
+  HO,N05  =  As05  +  HO,N03;  and  HO,N03  +  KO,C105 
=KO,N05+C103+HO. 

Hypochloric  Acid — C104.  A  deep-yellow  explosive  gas, 
evolved  by  heating  concentrated  Sulphuric  acid  with 
Chlorate  of  potassa,  3(KO,C105)  +  3(HO,S03)=2C104+ 
C107  +  3(KO,S03)  -J-  3HO. 

Chloric  Acid — C105.  Obtained  by  boiling  Chlorate  of 
Potassa  with  Hydrofluosilicic  acid. 

Test. — The  chlorates  evolve  pure  oxygen  when  heated. 

Perchloric  Acid — C107.  Shown  above  as  one  of  the 
products  in  formation  of  Hypochloric  acid. 

Compounds  of  Chlorine  with  Hydrogen. 

Hydrochloric  Acid— HC1. 

Preparation.  —  1st.'  When  equal  volumes  of  Hydrogen 
and  Chlorine  are  exposed  to  the  direct  sun-light  they  unite 
explosively.  2nd.  From  Sulphuric  acid  and  common  Salt. 
NaCl  -f  HO,S03  =  NaO,S03  +  HC1. 

Properties. — A  powerfully  acid  gas,  with  an  intense  at- 


BROMINE.  155 

traction  for  water.  The  latter  absorbs  418  times  its  bulk 
of  this  gas  to  form  the  liquid  known  as  Hydrochloric  acift. 
Unites  with-  metals,  forming  chlorides,  with  liberation  of 
hydrogen,  and  with  metallic  oxides,  to  form  chlorides  and 
water. 

Uses. — It  is  a  very  delicate  test  for  the  salts  of  silver 
and  for  ammonia.  It  is  employed  in  the  arts  for  preparing 
Labarraque's  solution,  Javelle  water,  bleaching  powder, 
for  the  extraction  of  gelatine  from  bones,  etc.  It  is  used 
alone,  or  in  aqua  regia,  to  dissolve  very  many  minerals, 
and  to  prepare  the  metallic  chlorides. 

Chloride  of  Nitrogen— NO  13.  A  fearfully  explosive  oily 
liquid,  formed  by  passing  chlorine  into  a  solution  of  sal 
ammoniac. 

Sym,  Br.  BROMINE.  Eq.  78.26. 

Discovered  by  M.  Balard  in  1826.  Named  from  (Spw^o?, 
a  disgusting  smell.  Found  in  sea-water,  especially  of  the 
Dead  Sea,  mineral  springs,  and  native  bromides.  Sp.  Gr. 
2.96. 

Preparation. — Bittern,  which  is  the  mother-liquor  of  sea- 
water,  after  the  less  soluble  salts  have  been  separated  by 
crystallization,  contains  various  bromides.  These  are  de- 
composed by  a  stream  of  chlorine  passed  through  the 
liquid,  and  the  bromine,  set  free,  dissolves  in  a  quantity 
of  ether  agitated  with  the  bittern  thus  treated. 

Properties. — When  separated  by  a  complicated  process 
from  the  ether,  Bromine  is  a  deep-red,  volatile  Hquid,  of  a 
very  suffocating  and  offensive  odor ;  freezes  at  about  19° 
and  boils  at  145° ;  bleaches  many  vegetable  colors ;  unites 
directly  with  many  of  the  metals,  sometimes  with  ignition, 
forming  bromides.  Bromide  of  silver  is  considerably  em- 
ployed in  photography.  Combines  with  Hydrogen  to 
form  Hydrobromic  acid,  HBr. 
Test. — Starch,  yellow. 


156  IODINE  —  FLUORINE. 

Sym.  I.  IODINE.  Eq.  126,36. 

Discovered  in  1812  by  M.  Courtois.  Named  from  £«%, 
violet-like.  Found  in  sea-water,  sea-weeds,  some  mineral 
springs,  and  as  iodides  of  lead  and  silver.  Sp.  Gr.  4.94. 

Preparation. — By  gently  heating  the  bittern  from  kelp, 
which  contains  Iodides  of  Sodium,  Magnesium,  etc.,  with 
Sulphuric  acid  and  Binoxide  of  Manganese.  Thus,  KI  -f 
MnO,  +  2  (HO,S03)  =  I  +  KO,S03  +  MnO,S03. 

Properties. — At  ordinary  temperatures  a  metallic  bluish- 
black  solid,  having  the  form  of  rhomboidal  scales  or  taper- 
ing octahedrons ;  at  225°  it  changes  to  a  liquid,  and  at 
347°  to  a  rich  intense  violet  vapor.  It  is  but  slightly 
soluble  in  water,  which  dissolves  about  0.007  of  its  weight 
at  ordinary  temperatures  ;  in  ether  and  alcohol  it  dissolves 
readily  and  forms  dark  reddish-brown  liquids.  Its  chem- 
ical affinities  are  like  those  of  chlorine  and  bromine,  but 
being  more  feeble  it  is  displaced  from  combination  by 
these  two  metalloids.  It  unites  with  hydrogen  to  form 
Hydriodic  acid,  HI,  and  with  oxygen  to  form  lodic  acid, 
I05,  and  Periodic  acid,  IO7,  but  none  of  these  compounds 
are  of  practical  importance. 

Test. — It  unites  with  starch,  in  the  presence  of  water, 
to  form  a  beautiful  blue  iodide  of  starch.  This  iodide 
loses  its  color  at  a  temperature  ol  1.65",  and  recovers  it 
again  on  allowing  the  liquid  to  cool. 

Uses. —  Iodine  alone,  or  in  combination  with  potassium, 
is  a  remedial  agent  for  goitres  and  scrofula.  The  iodides 
of  potassium,  sodium,  ammonium,  and  cadmium  are  em- 
ployed in  photography  to  iodize  the  collodion. 

Sym.  F.  FLUORINE.  Eq.  18.7. 

Discovered  by  Sir.  H.  Davy,  but  has  never  as  yet  been 
isolated  in  such  a  state  as  to  admit  of  satisfactorv  inves- 


FLUORINE. 


157 


tigation.     It  derives  its  name  from  fluor  spar,  in  which  it 
is  chiefly  found;  specific  gravity,  1.32  (theoretical). 

Hydrofluoric  Acid  —  HF.  A  highly  acid  gas  obtained  by 
acting  on  fluor  spar  (fluoride  of  calcium)  with  Sulphurous 
acid,  CaF+HO,S03=CaO,S03+HF. 

Use.  —  It  acts  powerfully  on  all  siliceous  matters,  and  is 
therefore  employed  in  etching  glass.     For  this  purpose  the 
plate,  or  other  object  to  be  etched,  is  coated  with  wax; 
the  design  to  be  produced  is  scratched  through  this.    Some 
Fluor  spar  in  coarse  powder  is  then  spread  in  a  shallow 
leaden  dish  (see  Fig.  138),  moistened  with  oil  of  vitriol 
warmed  with  a  spirit 
lamp.      As  soon  as 
fumes  comes  off  the 
lamp  is  removed,  and 
the    plate    set    face 
downwards     for     a 
minute  or  two  upon 
the  dish.      The   ex- 
posed  parts   of    the 

glass  are  corroded  by  the  fumes  and  acquire  the  appearance 
of  ground  glass,  thus  showing  the  design  upon  the  smooth 
glass  when  the  wax  has  been  removed  by  scraping  and 
rubbing  with  turpentine.  Thermometer  tubes,  chemical 
bottles,  etc.,  are  often  marked  in  this  way.  Plates  of  glass 
on  which  frost-like  crystals  have  been  formed,  by  spread- 
ing them  with  gum-water  containing  in  solution,  Nitre, 
Sulphate  of  Copper,  or  the  like,  may  be  thus  etched  so  as 
to  form  beautiful  objects  for  the  magic  lantern,  or  glass 
goblets  may  be  permanently  frosted  by  this  process.  A 
solution  of  HF  in  water  etches  likewise,  but  with  a 
smooth  surface. 
14 


158  CARBON, 

Sym.  C.  CARBON.  Eq,  6. 

Carbon  occurs  in  three  forms : 

1st.  Diamond,  whose  name  is  a  corruption  of  adamant 
(from  a,  privative  ;  and  bapdu,  I  subdue),  invincible.  Hard- 
est of  all  substances,  cannot  be  cut  except  by  its  own  dust; 
but  scratches  all  other  minerals  and  metals.  Sometimes 
colored,  but  usually  limpid  ;  infusible  at  all  temperatures  ; 
combustible  at  a  white  heat  with  formation  of  Carbonic 
acid  gas  ;  of  a  high  refractive  and  dispersive  power;  feebly 
phosphorescent  when  brought  into  a  dark  room  after  ex- 
posure to  light.  It  crystallizes  in  octahedra  and  tetra- 
hedra,  oftentimes  with  curved  faces.  It  is  probably  of 
vegetable  origin. 

Uses.  —  As  an  ornament,  cut  as  a  rose  or  'brilliant;  the 
former  having  the  under  surface  flat,  and  the  upper 
elevated,  en  dome,  without  table,  and  reflecting  light  from 
24  facets ;  the  brilliant  is  cut  into  symmetrical  facets  on 
both  lower  and  upper  faces.  2nd.  For  cutting  glass,  for 
delicate  pivot-rests,  and  as  a  grinding  and  polishing 
powder. 

2nd.  Graphite  or  Plumbago. — A  very  friable  substance, 
soft  and  greasy  to  the  touch,  and  of  a  metallic  leaden- 
gray  lustre.  It  is  largely  worked  at  Ticonderoga,  New 
York,  and  at  Brandon,  Vermont.  It  is  sometimes  found 
in  brilliant  six-sided  spangles,  which  may  also  be  arti- 
ficially produced  by  dissolving  charcoal  in  melted  iron. 

Uses. — Lead-pencils ;  mixed  with  fire-clay,  it  is  made  into 
"  black-lead"  crucibles  for  melting  gold,  silver,  etc. ;  it  is 
rubbed  over  iron-castings  to  preserve  them  from  rust  — 
stove-polish  ;  to  relieve  the  friction  of  carriage  axles,  wheels 
of  machinery,  and  even  of  clocks;  to  polish  gun-bullets; 
smeared  over  the  wax  medals  in  an  electro-plating  bath 
to  cause  the  deposition  of  gold  and  silver  upon  their 
surface. 


CARBON.  159 

8rd.  Amorphous  Carbon.  —  In  consequence  of  its  infusi- 
bility  carbon  presents  itself  in  a  variety  of  aspects  accord- 
ing to  the  structure  of  the  body  from  which  it  was  formed 
and  the  manner  of  its  preparation,  viz. : 

(a)  Metallic  Carbon.  —  A  metallic  coating  formed  by 
the  contact  of  the  carburetted  hydrogen  gases  produced 
in  the  distillation  of  coal  with  the  red;hot  sides  of  the 
retort.  It  is  an  excellent  material  for  the  carbon  points 
of  the  electric  light,  and  for  the  positive  pole  of  Bunsen's 
battery. 

(6)  Charcoal  is  formed  by  burning  stacks  of  wood  which 
are  covered  over  with  leaves  and  dirt  to  prevent  a  free 
access  of  air.  The  charcoal  of  light  woods,  such  as  black 
alder  and  willow,  is  largely  consumed  in  gunpowder.  As 
a  powder,  charcoal  is  used  for  polishing  copper  and  bronze; 
as  a  dust,  it  is  sprinkled  over  meats  to  preserve  them  from 
decay  ;  in  lumps,  to  absorb  noxious  gases.  So  the  charring 
of  the  ground  end  of  fence  posts  secures  them  from  rot. 

(c)  Coke  is  obtained  by  distilling  off  the  water,  tar,  and 
gas  from  bituminous  coal ;   100  tons  of  the  latter  offering 
50  or  60  tons  of  coke.     It  produces  a  greater  heat  than 
any  other  combustible,  and  is  largely  employed  in  blast 
furnaces,  forges,  etc. 

(d)  Lampblack  is  condensed  upon  the  sides  of  chambers, 
in  which  resins,  fats,  etc.,  are  burnt  with  an  insufficient 
draft  of  air.     It  is  employed  in  painting ;  mingled  with 
two-thirds  its  weight  of  clay,  to  form  black  drawing-cray- 
ons;  intimately  mixed  with  dry  linseed-oil  to  make   an. 
indelible  printer's  ink.     Manuscripts,  written  in   an  ink 
composed  of  lampblack  and  gum-water,  have  been  exhumed 
at  Herculaneum  and  Pompeii,  still  perfectly  legible. 

(e)  Animal  charcoal  is  made  by  burning  bones  in  close 
vessels.     It  serves  as  an  antidote  to  vegetable  poisons, 
but  its  principal  use  is  to  refine  sugar.     After  a  while  it 
loses  its  power  of  decolorizing  syrup  ;  but  it  may  be  revivi- 


160  COMPOUNDS    WITH    OXYGEN. 

fied  by  drying,  saturating  with  Hydrochloric  acid  garf, 
washing,  and  reburning.  (See  Franklin  Institute  Journal, 
V.  49,  p.  250.)  Ex.  A  rich  solution  of  indigo,  filtered 
through  animal  charcoal,  loses  its  color  entirely. 

Compounds  with  Oxygen. 

Carbonic  Oxide— CO.    Sp.  Gr.  0.972. 

Preparation. — Heat  1  part  of  Ferrocyanide  of  Potassium 
with  10  parts  of  sulphuric  acid.  K2FeC6N3  -f  6(HO, 
S03)  -f  6HO  =  6CO  -f  2(KO,SO3)  -J-  FeO,SO3  -f  3(NH A 
S03) 

Properties. — A  colorless,  inodorous,  poisonous  gas ;  ex- 
tinguishes flame,  but  burns  itself  with  a  purplish  blue 
flame,  easily  extinguished.  Seen  in  coal  fires  where  there 
is  a  lack  of  air. 

Carbonic  Acid — CO2.  (Fixed  air,  choke-damp.)  Sp.  Gr. 
1.521. 

Sources. — Combined  with  lime,  as  limestone,  forms  one- 
seventh  of  the  solid  crust  of  the  earth's  surface.  United 
with  iron,  copper,  zinc,  etc.,  forms  many  valuable  ores. 
Constitutes  one-thousandth  part  of  our  atmosphere. 

Preparation.  —  By  decomposing  a  carbonate  by  any 
strong  acid.  Ex.  NaO,CO2  +  HO,SO3=  NaO,S03  -f  HO 
+  C02. 

Thus  we  place  in  a  vessel  such  as  A  (Fig.  139)  some 
common  washing  soda  (Carbonate  of  Soda),  and  pour 
upon  it  dilute  Sulphuric  acid.  The  gas  is  then  freely 
developed,  and  may  be  collected  by  displacement.  This 
gas  is  also  produced  in  all  ordinary  cases  of  combustion 
and  in  respiration.  The  amount  of  CO2  exhaled  by  a 
man  in  twenty-four  hours,  is  about  26^  ounces.  This 
would  give  for  the  inhabitants  of  the  world,  about  820,000 
tons  per  day.  Fortunately,  plants  reverse  this  action. 

Properties. — The  weight  of  this  gas  is  very  notable.  It 
may  be  poured  from  one  vessel  to  another  and  weighed 


CARBON. 


161 


readily  on  a  large  scales  in  a  grocer's  paper-bag,  or  in  a 
wooden  bucket. 

Many  of  its  properties  may  be  well  exhibited  by  arrang- 
ing  an  artificial  grotto,  Fig.  139,  and   allowing   the  gas 

Fig.  139. 


from  the  bottle,  A,  to  flow  into  it.  This  will  settle  like 
water  at  the  lower  part,  and  a  taper  will  burn  within 
until  lowered  beneath  the  surface  of  the  gas.  A  little 
slide  being  then  opened  in  the  side  of  the  box,  the  gas 
may  be  drawn  off  into  vessels,  poured  from  them  over 
candles  so  as  to  extinguish  them,  etc. 

It  directly  interferes  with  and  prevents  combustion.  It 
has  therefore  been  used,  by  Sir  Goldsworthy  Gurney,  in 
fire-engines  which  pour  Carbonic  acid  instead  of  water 
upon  a  burning  building,  and  for  putting  out  fires  in  burn- 
ing mines.  Does  not  support  respiration  ;  and  when  formed 
in  mines  by  explosions  of  fire-damp,  it  is  the  choke-damp 
so  fatal  to  miners.  Under  the  influence  of  light,  it  is 
decomposed  in  the  leaves  of  plants.  The  carbon  being 
essential  to  vegetable  growth,  is  retained  by  the  plant; 
while  the  oxygen  is  returned  to  the  atmosphere,  in  order 
that  animal  life  may  be  sustained.  It  is  soluble  in  water, 
and  when  held  in  solution  under  pressure,  makes  soda- 
water. 

Liquid  Carbonic  Acid.— Under  a  pressure  of  40  atmos- 

14* 


162  CARBON. 

pheres,  or  600  Ibs.  to  the  square  inch,  Carbonic  acid  gas  is 
condensed  to  a  colorless  liquid. 

Solid  Carbonic  Acid.  —  When  a  jet  of  this  liquid  is  thrown 
into  a  metallic  receiver  filled  with  holes,  the  vessel  is  seen 
to  fill  rapidly  with  a  flaky  snow.  This  is  solid  Carbonic 
acid,  formed  by  the  great  cold  —  about  150°  —  given  out  in 
the  very  rapid  evaporation  of  part  of  the  liquid  Carbonic 
acid.  By  mixing  solid  Carbonic  acid  with  ether,  and  evap- 
orating under  the  receiver  of  an  air-pump,  the  intensest 
cold  yet  known  is  produced.  This  mixture,  as  it  were, 
burns  the  hand  if  placed  upon  it,  and  causes  active  in- 
flammation. 

Test.  —  Lime-water  is  so  delicate  a  test  that  it  is  rend- 
ered cloudy  by  blowing  the  air  from  the  lungs  through 
it  for  a  very  short  time. 

Compounds  of  Carbon  with  Hydrogen. 

Protocarburetted  Hydrogen  —  C2H4.  (Light  Carbu- 
retted  Hydrogen).  Exists  native,  as  fire-damp  in  coal- 
mines, and  the  inflammable  air  of  marshes  —  marsh-gas. 
Prepared  by  heating  4  parts  of  acetate  of  soda  (which 
must  be  first  dried),  4  parts  of  caustic  potash,  and  6  parts 
quicklime,  powdered  and  mixed  in  a  strong  glass  flask, 
2(NaO,C4H3Oa)  -f  KO,HO  +  CaO,HO  =  2(NaO,CO,)  + 
KO,  C02+  CaO,  C0a+  2  C2  H4. 

Properties.  —  A  colorless,  transparent  gas.  Sp.  Gr.  0.555. 
Extinguishes  flame,  but  burns  itself  with  a  pale  yellow 
flame  ;  mixed  with  air  and  lighted,  explodes. 

Bicarburetted  Hydrogen  —  C4H4.  Sp.  Gr.  0.98.  Also 
called  Heavy  Carburetted  Hydrogen  and  Olefiant  Gas. 

Preparation.  —  One  measure  of  alcohol  is  heated  with  3 


-f  C4H4.     To  avt)id  frothing,  we  pour  sand  into  the  flask 
till  all  the  liquid  is  aborbed  by  it. 

Properties.  —  A  colorless  gas,  with  a  sweet,  alliaceous 


COMPOUNDS    WITH    HYDROGEN. 


163 


oder;  soluble  in  about  12  times 
its  bulk  of  cold  water;  liquefi- 
able  under  great  pressure ;  not 
a  supporter  of  combustion.  Very 
inflammable,  burning  with  a 
white  luminous  flame.  Combines 
with  chlorine  to  form  Dutch 
Liquid,  C4H4C12. 

Remark. — The  two  preceding 
gases  are  the  principal  constitu- 
ents of  coal-gas.  Prepared  by 
distilling  bituminous  coal  in 
large  iron  retorts  ;  purifying 
the  gases  evolved  by  passing 
it  through  vessels  filled  with 
spray  of  water  (which  absorbs 
their  ammoniacal  impurities), 

Fig.  141. 


164  CARBON    AND    NITROGEN. 

and  through  vessels  containing  moist  lime  (which  absorbs 
the  sulphur  and  carbon  compounds),  and  lastly,  storing 
them  in  large,  self-adjusting  gas  holders;  whose  principle 
is  illustrated  by  the  smaller  apparatus  figured  in  the  cuts. 
Fig.  140,  and  Fig.  141.  As  the  gas  flows  in,  the  inner 
drum  rises,  giving  space;  as  it  escapes,  this  sinks,  so 
diminishing  the  capacity  of  the  vessel. 

Compound  of  Carbon  with  Nitrogen. 

Cyanogen— C,N  or  Cy.    Sp.  Gr.  1.82. 

Source.  —  Cyanogen  is  formed,  in  combination  with 
potassium,  by  heating  organic  substances  containing 
nitrogen,  such  as  fibrine,  gelatine,  skins,  etc.,  with 
potash. 

Preparation. — Obtained  by  heating  Cyanide  of  Mercury. 
HgC2N  =  Hg  +  C2N. 

Properties. — A  colorless,  soluble  gas ;  liquefiable  by  a 
pressure  of  four  atmospheres.  Its  odor  resembles  that 
from  bitter  almonds.  Burns  with  a  dark  blue  flame  fringed 
with  purple.  In  chemical  properties,  it  must  be  classed 
with  chlorine  and  bromine  ;  uniting,  like  them,  with  hydro- 
gen to  form  an  acid,  and  with  the  metals  to  form  salts. 
It  was  the  first  one,  among  many  compound  bodies  since 
discovered,  which  was  found  to  play  the  part  of  an  ele- 
ment ;  and  the  discovery  of  this  "  Compound  Radical,"  as 
such  bodies  are  called,  by  Gay  Lussac,  in  1814,  greatly 
simplified  modern  chemistry. 

Uses. — Its  combination  with  hydrogen,  Hydrocyanic,  or 
Prussic  acid,  HCy,  is  a  fearful  poison,  whose  proper  anti- 
dote is  chlorine  or  ammonia,  cautiously  inhaled.  Diluted, 
however,  with  50  times  its  weight  of  water,  it  is  employed 
to  allay  nausea,  and  as  a  lotion  in  skin  diseases.  Cyanide 
of  Potassium,  KCy,  energetically  dissolves  -the  cyanides 
of  gold  and  silver,  and  forms  with  them  double  cyanides, 
which  constitute  the  gold  and  silver  baths  in  Electro- 


BORON.  165 

plating.     Alone,  Cyanide   of   Potassium  is  excellent  for 
fixing  Collodion  Positives. 

Compound  of  Carbon  with  Sulphur. 

Bisulphide  of  Carbon — C,S2.  Sulphocarbonic  Acid.  Sp. 
Gr.  1.272. 

Preparation. — Prepared  by  passing  sulphur  vapor  over 
ignited  charcoal  and  condensing  the  result  by  cold.  A 
transparent,  colorless  liquid,  insoluble  in  water,  of  most 
disgusting  smell. 

Uses. — To  dissolve  sulphur,  phosphorus,  many  resins, 
oils,  etc.  Owing  to  its  great  refracting  and  dispersive 
power,  it  is  employed  in  prisms  of  the  spectroscope  and 
other  optical  instruments ;  in  the  construction  of  thermom- 
eters for  measuring  intense  cold,  since  it  cannot  be  frozen ; 
along  with  tallow  and  phosphorus,  as  a  substitute  for 
black-lead  in  electro-silvering  large  medals,  etc.  To  re- 
move grease-stains. 

Sym.  B.  BORON.  Eq.  1.09. 

Discovered  by  Davy,  1801. 

Preparation. — The  double  fluoride  of  boron  and  po- 
tassium is  heated  with  an  equal  weight  of  potassium. 
KF,BF3  +  3K  =  4KF  -f  B. 

Modifications.  —  1st.  As  thus  obtained,  Boron  is  an 
amorphous  olive-green  powder,  which  burns  when  heated 
in  the  air  to  a  point  below  redness,  forming  Boracic  acid. 
In  this  condition  it  corresponds  to  charcoal. 

2nd.  As  octahedra;  which  are  very  hard,  highly  re- 
fracting ;  fusible  only  under  intense  heat,  and  in  all  respects 
like  Diamond. 

3rd.  As  scaly,  hexagonal  plates,  resembling  Graphite. 

Compound  with  Oxygen. 
Boracic  Acid— B03.     Sp.  Gr.  1.8. 
Source. — Discharged   from   small    craters    or    soffioni 


166  SILICON. 

along  with  sulphuretted  hydrogen  and  steam,  into  the 
bottom  of  the  Tuscan  lagunes.  The  waters  of  these 
lagunes  are  evaporated  until  the  Boracic  acid  which  they 
hold  in  solution  crystallizes  out.  The  requisite  heat  is 
derived  from  the  vapors  of  the  soffioni,  which  are  con- 
ducted by  stone  passages  beneath  the  evaporating  pans. 

Preparation. — Neutralizing  Biborate  of  Soda  with  Sul- 
phuric acid,  NaO,2B03  +  HO,S03  +  Ag  =  NaO,S03  + 
2(3HO,B03). 

Properties. — It  contains  3  equivalents  of  water  of  crys- 
tallization separable,  from  the  acid  at  a  red  heat ;  tinges 
flames  green,  and  combines  with  bases  to  form  borates,  the 
most  important  of  which  is  biborate  of  soda  or  borax.  The 
latter  is  also  imported  largely  from  Thibet,  under  the 
name  of  tincal. 

Uses. — Borax  is  employed  in  medicine,  under  the  name 
of  sedative  salt  of  Homberg.  As  a  flux  in  blowpipe  anal- 
ysis, and  in  welding  and  soldering. 

Sym.  Si.  SILICON.  Eq.  21.35. 

Discovered  by  Berzelius,  1824. 

Source. — Exists  in  three  forms,  like  Carbon  and  Boron : 
(a)  As  obtained  in  the  above  reaction,  a  dark-brown  pow- 
der, burning,  when  heated  in  the  air,  to  Silicic  acid,  Si03 
(6)  Resembling  diamond,  (c)  Graphitoidal. 

Preparation.  —  Prepared  like  Boron:  KF,SiF3-f-3K= 
4KF+Si. 

Compound  with  Oxygen. 

Silicic  Acid,  Silex,  Silicia,  Si03.     Sp.  Gr.  2.66. 

Source.  — Forms  45  per  cent,  of  the  solid  crust  of  the 
globe,  occurring  pure  as  quartz  (rock  crystal) ;  almost  pure 
in  chalcedony,  flint,  agate,  and  carnelian;  chief  ingredient 
of  sandstone  rock.  Combined  as  a  mineral  acid  with 
almost  every  known  base,  it  forms  a  vast  variety  of  ores 


SILICON.  167 

and  rocks.    It  is  found  in  small  quantities  in  the  ashes  of 
nearly  all  vegetables. 

Preparation.  —  The  process  consists  of  two  parts:  (a) 
equal  quantities  of  powdered  glass  and  fluor  spar  are  heated 
with  sulphuric  acid ;  the  hydrofluoric  acid  generated  from  the 
fluoride  of  calcium  and  sulphuric  acid  decomposes  the  silicic 
acid  in  glass,  forming  gaseous  terfluoride  of  silicon,  SiF3; 
(6)  This  gas  is  made  to  bubble  through  a  large  amount 
of  water  in  another  vessel ;  the  water  is  decomposed  by  it, 
and  hydrofluosilicic  acid,  3HF,2SiF3,  together  with  gluti- 
nous silica  is  formed  ;  thus,  (a)  9CaF+9HO,SO3=9HF+ 
9CaO,S03,  and  9HF  +  3Si03=9HO+3SiF3.  (6)  3SiF3  + 
3HO=Si03  +  3HF,2SiF3. 

Properties. — :(a)  Physical.  Anhydrous  Silicic  acid  is  a 
snowy-white,  tasteless  solid,  infusible  in  the  fiercest  blast 
of  a  furnace,  but  can  be  spun  out  before  the  oxyhydrogen 
blow-pipe  into  very  fine  threads. 

(6)  Chemical.  Silicic  acid  exists  in  two  entirely  different 
forms :  — 

1st.  Insoluble  Silica.  Anhydrous  Silicic  acid,  after  hav- 
ing been  heated  to  redness,  is  insoluble  in  water  and  all 
acids,  except  hydrofluoric.  Fused  with  the  alkalies  or 
their  carbonates,  it  is  converted  into 

2nd.  Soluble  Silica.  In  this  way  the  chemist  is  able  to 
attack  and  dissolve  with  acids  a  great  number  of  siliceous 
minerals. 

•  Though  Silica  is  a  very  feeble  acid,  yet  when  heated 
with  compounds  of  the  strongest  acids,  as  the  sulphates, 
it  can  expel  them  on  account  of  its  non-volatility,  or  fixed- 
ness. 

Varieties.  —  Crystallized  in  ice-like  hexagonal  prisms,  it 
is  known  as  rock  crystal;  stained  by  nickel  an  apple- 
green,  chrysoprase  ;  by  sesquioxide  of  iron,  clear  yellow 
and  bright  red,  false  topaz  and  carnelian  ;  by  sesquioxide 
of  manganese,  violet,  amethyst.  When  the  color  is  centred 


168  SULPHUR. 

in  blood-red  spots,  it  is  known  as  blood-stone,  when  grouped 
in  concentric  layers  of  varying  tint,  as  sardonyx,  Mocha, 
stone,  riband  jasper,  and  the  Lydian  or  touch-stone. 
When  the  Silica  is  splintered  internally,  and  sends  from 
its  interior  broken  beams  of  light,  hyacinth  red,  and  golden 
and  fiery  crimson,  it  is  called  girasol  and  noble  opal. 

Uses. — As  a  jewel ;  in  irregular  conchoidal  masses,  gun- 
flints;  as  agate  rests  for  the  knife-blades  of  delicate 
balances;  as  tripoli  —  a  granular  Silicic  acid,  the  remains 
of  shell-fish — for  polishing.  In  the  form  of  grain  or  sand, 
in  all  glass-making  and  pottery ;  as  sand  compacted  by  a 
natural  cement  of  lime  or  silica,  an  invaluable  building 
material  —  sandstone,  etc. 


Sym.  S.  SULPHUR.  Eq.  16. 

Sources. — Found  native  in  the  volcanic  districts  border- 
ing upon  the  Mediterranean,  especially  at  the  Solfatara 
near  Naples,  and  at  Mt.  Etna;  in  South  America,  India, 
and  the  volcanic  islands  of  the  Pacific.  Many  valuable 
ores  are  sulphides,  such  as  cinnabar,  smaltine,  kupfer- 
nickel,  pyrites,  and  blende;  and  as  a  sulphate, in  gypsum, 
heavy  spar,  and  celestine,  it  no  less  abounds.  In  combi- 
nation with  hydrogen,  it  gives  to  many  mineral  waters 
their  offensive  smell  and  taste  ;  it  is  present  in  oil  of  mus- 
tard, garlic,  assafcetida,  and  onions ;  and  accompanies  the 
petroleum  which  flows  from  Canadian  wells. 

Preparation.  —  Purified  from  the  blue  clay,  gypsum,  or 
rock  salt,  in  which  it  is  found  by  sublimation.  It  is  poly- 
morphous, and  has 

Modifications. — 1st.  As  found  native,  or  as  obtained  by 
evaporating  a  solution  of  Sulphur  in  bisulphide  of  Carbon, 
it  is  a  semitrausparent,  amber  yellow,  rhombic  octahedron 
In  this,  which  is  its  stable  form,  it  has  a  sp.  gr.  2.05,  and 
fuses  at  239°. 


SULPHUR.  169 

2nd.  Crystallizes  from  fusion  in  transparent,  brownish- 
yellow,  oblique  rhombic  prisms;  sp.  gr.  1.98 ;  fuses  at  248°. 
Unstable,  shortly  becomes  opaque,  and  crumbles  into  the 
first  form. 

3rd.  Heated  above  482°,  and  suddenly  cooled,  assumes 
the  condition  of  an  amber-colored  elastic  solid.  But  even 
its  amorphous  form  is  unstable,  and  after  a  while  becomes 
brittle  by  crystallizing  into  octahedra.  A  red  and  black 
modification  likewise  exist. 

Properties. — Burns  at  460°,  and  forms  Sulphurous  acid  ; 
sublimes  into  flowers  ;  when  heated  and  run  into  moulds 
forms  Roll-sulphur  or  brimstone.  Combines  readily  with 
Chlorine,  Bromine,  and  Iodine ;  has  such  an  affinity  for 
metals  that  many  of  them,  in  powder,  will  burn  vividly, 
if  heated  in  its  vapor,  and  form  sulphides  or  sulphurets. 

Uses. — It  is  applied  in  taking  impressions,  and  in  making 
moulds  or  medals ;  in  vulcanizing  India-rubber ;  for 
matches  ;  constitutes  10  per  cent,  of  gunpowder.  It  was. 
selected  as  a  lubricant  for  the  axles  of  the  car  on  which 
the  monster  Fort  Pitt  cannon  was  transported  from  Pitts- 
burg  to  Philadelphia.  It  is  prescribed  for  constipation, 
gout,  asthma,  etc.;  externally  as  an  ointment  for  cuta- 
neous diseases,  and  both  internally  and  externally  for 
chronic  rheumatism. 

Compounds  with  Oxygen. 

Sulphurous  Acid— S02.    Sp.  Gr.  2.24T. 

Preparation. — By  burning  Sulphur  in  Oxygen,  or  by 
heating  Sulphuric  acid  with  copper,  Cu  +  2(HO,S03)  = 
CuO,S03  +  S02  -f  2HO. 

Properties.  —  A  suffocating,  irrespirable  gas ;  become? 
liquid  at  0°  ;  water  absorbs  44  times  its  bulk  of  this  gas, 
which  must  therefore  be  collected  over  mercury.  May  be 
combined  with  many  bases  by  being  transmitted  through 
water  holding  the  metallic  oxide  or  carbonate. 


170  SULPHUR. 

Uses.  —  Owing  to  the  property  which  Sulphurous  acid 
possesses  of  bleaching  most  coloring  matters,  it  is  largely 
employed  to  whiten  silk  and  wool.  Chlorine  cannot  be 
employed  to  bleach  these  two  fabrics,  because  it  tinges 
them  yellow.  The  moistened  goods  are  simply  thrown 
over  rails  in  large  rooms,  where  Sulphur  is  kept  burning. 
To  bleach  isinglass  (gelatin)  and  the  straw  for  bonnets, 
hats,  etc.  ;  to  take  out  fruit-stains  from  pocket-handker- 
chiefs, dresses,  etc. ;  to  free  infected  places  from  miasma 
and  infection,  and  to  purify  lazarettos.  In  casks,  it  pre- 
vents the  wine  they  contain  from  turning  into  vinegar :  it 
is  sufficient  to  burn  in  them  a  little  sulphur.  Sulphurous 
acid  in  combination  with  Soda,  as  Sulphite  of  Soda,  NaO, 
S02,  is  employed,  under  the  name  of  antichlorine,  to  com- 
bine with  the  excess  of  chlorine,  or  hypochlorite  of  lime, 
which  has  been  used  in  bleaching  paper-pulp,  and,  by 
neutralizing  it,  prevent  the  evil  effects  which  would  ensue 
from  an  overdose  of  chlorine. 

Sulphuric  Acid  —  S03.  Distils  over  from  fuming  Nord- 
hausen  acid  as  a  white,  silky  solid,  devoid  of  acid  prop- 
erties, HO,2S03=  HO  +  2S03.  Possesses  an  intense 
affinity  for  water,  and  when  combined  with  it  as  a  hy- 
drate forms  what  is  generally  known  as  concentrated  oil 
of  vitriol,  or  Sulphuric  acid,  HO,S03.  Sp.  Gr.  1.97  ;  melts 
at  65°.  There  are  four  hydrates. 

1.  Dihydrate  —  HO,2S03.      Formed  by  dissolving  the 
Anhydride  in  the  Monohydrate. 

2.  Monohydrate  —  HO,S03.     Formed  by  concentrating 
in  platinum  stills  the  ordinary  brown  acid  of  commerce. 
An  intensely  acrid,  powerful  acid ;  destroys  organic  sub- 
stances by  its  strong  attraction  for  the  elements  of  water ; 
for  the  same  reason  very  valuable  as  a  desiccating  agent. 
Sp.  Gr.  1.842.     Freezes  at  —30  ;  boils  at  640°. 

3.  Bihydrate  —  2HO,S03.      Obtained  when  sufficient 
water  has  been  added  to  the  Monohydrate  to  reduce  its 


SULPHUR,  171 

density  to  1.78.  Crystallizes  in  beautiful  rhombic  prisms 
at  47°;  boils  at  435°. 

4.  Terhydrate  —  3HO,SO3.  By  evaporating  at  212°  in 
vacuum  a  still  more  dilute  acid  till  it  ceases  to  lose  weight. 
Sp.  Gr.  1.63;  boils  at  348°. 

Preparation. — Process  of  the  Leaden  Chambers.  Con- 
sists in,  1st.  A  deoxidation  of  Nitric  acid  by  Sulphurous 
acid,  S02  +  HO,N05  =  HO,S03  -f  N04.  2d.  A  union  of 
the  Hyponitric  acid  so  formed  with  2  equivalents  of  sul- 
phurous acid  and  an  indefinite  quantity  of  water,  to  form 
a  thick  crystalline  compound  (N04-f  2S02+Aqua).  3d. 
An  immediate  decomposition  of  this  compound  in  contact 
with  steam,  and  the  formation  of  2  equivalents  of  sul- 
phuric acid,  which  remain  in  solution,  and  1  equivalent 
of  Binoxide  of  Nitrogen;  thus,  N04  -f  2SO,+Aq.=nN02 
-f  2(HO,S03)  -f  aq.  4th.  A  union  of  this  N02  with  20 
to  form  N04  again.  The  NO4  so  formed  repeats  the 
second  step ;  more  N02  is  formed,  and  so  the  operation 
continues  by  the  carrying,  on  the  part  of  the  Binoxide 
of  Nitrogen,  of  Oxygen  to  the  Sulphurous  acid. 

The  very  dilute  acid  so  formed  is  concentrated  to  a  den- 
sity of  1.72  by  evaporation  in  leaden  pans,  and  called 
Brown  acid ;  and  by  further  concentration  in  vessels  of 
platinum  becomes  oil  of  vitriol  of  commerce,  whose  den- 
sity should  be  1.845. 

We  can  demonstrate  this  action  on  the  small  scale  very 
completely  with  the  apparatus  shown  in  Fig.  142.  Into 
the  large  glass  vessel,  F,  we  pass  Sulphurous  acid  from 
the  flask,  A,  and  Nitric  oxide  (which,  with  the  air  present, 
at  once  forms  N04)  from  the  gas-bottle,  B.  The  reaction 
soon  commences,  and  F  becomes  coated  with  silky  crys- 
tals, We  then  pass  in  steam  from  C,  when  these  crys- 
tals are  decomposed,  and  red  fumes  reappear ;  then  more 
Sulphurous  acid  from  A  is  admitted,  and  air  is  forced  in 
through  D,  while  excess  of  gas  escapes  by  tube  E,  leading 
to  a  chimney. 


112 


SULPHUR. 


Uses. — In  the  manufacture  of  Carbonates  of  Soda,  Nitric 
and  Hydrochloric  acids,  Chlorine,  Phosphorus,  Alum,  Cop- 
peras, Ether,  and  many  other  chemicals ;  in  making  can- 
dles, in  refining  coal-oil,  etc. 

Fig.  142. 


Test.  —  Gives  a  white  precipitate  with  Chloride  of  Ba- 
rium, Bad  +  HO,S03  =BaO,S03  +  HC1. 

Other  Compounds  of  Sulphur  and  Oxygen, 

Not  important,  except  Hyposulpliurous  acid,  S202.  This 
is  employed  in  combination  with  soda,  as  Hyposulphite  of 
Soda  (NaO,S202),  to  fix  the  photographic  image;  that  is, 
to  decompose  the  Chloride  of  Silver  which  has  not  been 
affected  by  the  light  while  in  the  camera,  and  which  if 
allowed  to  remain  on  the  paper,  after  removal  from  the 
camera,  would  darken  and  obliterate  the  picture.  The 
result  of  this  decomposition  is  Hyposulphite  of  Silver 
and  Chloride  of  Sodium,  both  of  which,  unlike  Chloride  of 
Silver,  are  soluble  in  water,  and  may  be  washed  off;  thus, 
JSTaO.SA  +  AgCl  =  AgO,S,02  +  NaCl.  The  Hyposul- 


SULPHUR. 


173 


Fig.  143. 


phites  of  Silver,  Gold,  and  Platinum  have  not  succeeded 
well  as  electro-plating  baths  for  deposition  of  their  respec- 
tive metals. 

Compound  with  Hydrogen. 

Hydrosulphiiric  Acid  —  HS.     Sulphuretted  Hydrogen. 
Sp.  Gr.  1.17. 

Preparation. — By  reaction  of  diluted  Sulphuric  acid  on 
Sulphide  of  Iron,  FeS  +  HO,S03= 
FeO,S03  +  HS,  or  of  Hydrochloric, 
acid  on  Tersulphide  of  Antimony, 
SbS3  +  3HC1  =  SbCl  +  3HS.  The 
Sulphide  of  Iron  may  be  placed  in  a 
flask  like  Fig.  143,  and  dilute  acid 
introduced  by  the  tube,  as  required 
to  evolve  the  gas.  Emitted  from  or- 
ganic matters  containing  Sulphur, 
from  drains,  sinks,  etc.  It  is  this 
gas  which  blackens  spoons  employed 
in  eating  eggs,  by  forming  on  their 
surface  black  Sulphide  of  Silver, 
AgS. 

Properties. — A  colorless  gas,  smell- 
ing like  rotten  eggs ;  liquefied  under 
17  atmospheres;  poisonous;  burns 
with  a  pale-blue  flame,  forming  water 
and  Sulphurous  acid ;  instantly  decomposed  by  the  halo- 
gens, owing  to  their  superior  affinity  for  Hydrogen. 

Test.  —  A   black   precipitate    with    Acetate    of    Lead, 
PbO,C4H303  +  HS  =  HO,C4H303  -f  PbS. 

Uses.  —  Since  it  precipitates  the  metals  from  their  acid 
solutions,  by  forming  with  them  differently  colored  Sul- 
phides, insoluble  in  water  or  acids,  it  is  incessantly  used 
in  the  laboratory  to  determine  the  various  metals  and 
separate  them  from  each  other.  Sulphur  baths,  or  those 
15* 


174  SELENIUM — PHOSPHORUS. 

containing  sulphuretted  hydrogen  dissolved  in  water,  are 
prescribed  for  cutaneous  diseases. 


Sym.  Se.  SELENIUM.  Eg,  39.28. 

Discovered  by  Berzelius,  1817.     Sp.  Gr.  4.5. 

Sources.  —  Found  combined  with  certain  metallic  sul- 
phides ;  very  rarely  as  Selenides.  Obtained  by  a  compli- 
cated treatment  of  a  red  deposit  formed  in  the  works  at 
Fahlun,  where  sulphuric  acid  is  made  from  pyrites  con- 
taining Selenium. 

Properties.  —  As  thus  obtained  Selenium  is  a  reddish- 
brown,  semimetallic-looking,  amorphous  solid;  sp.  gr.  4.3.; 
fuses  at  220°,  and  evolves  when  heated  a  disgusting  smell. 
It  resembles  sulphur  very  closely,  existing  in  three  corre- 
sponding modifications:  1st,  amorphous,  which  has  just 
been  described;  2d,  vitreous;  3d,  as  crystallized  from 
solution  in  Bisulphide  of  carbon,  rhomboidal  prisms.  Its 
compounds  with  Hydrogen  and  Oxygen  are  analogous  to 
those  which  sulphur  forms  with  the  same  elements,  viz., 
Hydroselenio  acid,  HSe ;  Selenous  acid,  Se02;  and  Se- 
lenic  Acid,  Se03;  and,  like  sulphur,  it  combines  directly 
with  Chlorine  and  Iodine. 

Sym.  P.  PHOSPHORUS.  Eq.  32. 

Named  from  $w$,  light;  and  $op6?,  carrying.  First 
obtained  by  Brandt,  of  Hamburg,  in  1660.  Found  as  a 
phosphate  of  lime  in  many  rocks.  By  their  decom- 
position phosphate  of  lime  passes  into  the  soil,  from 
thence  into  many  plants,  and  finally  into  the  bones  of 
animals,  forming  their  chief  earthy  constituent ;  phos- 
phorus seems  essential  to  the  brain  and  nerve  tissue,  and 
is  an  ingredient  of  albumne  and  fibrin. 

Preparation.  —  When  bones  are  burned,  they  are  con- 
verted into  a  tribasic  phosphate  of  lime,  3CaO,PO5.  If 


PHOSPHORUS.  1T5 

this  be  treated  with  Sulphuric  acid,  Superphosphate 
of  lime  is  formed;  thus,  3CaO,P05  -f  2(HO,S03)  = 
2HO,CaO,P05  +  2(CaO,S03).  The  acid  solution  is 
filtered  from  the  insoluble  sulphate  of  lime,  evaporated  to 
a  syrup,  and  then  heated  to  redness,  with  one-fourth  its 
weight  of  charcoal.  The  superphosphate  of  lime  is  first 
decomposed  into  bone-ash  and  tribasic  phosphoric  acid, 
3(2HO,CaO,P05)=3CaO,P05+2(3HO,P05)  ;  afterwards 
the  hydrated  phosphoric  acid  so  formed  is  deoxidized  by 
the  charcoal,  2(3HO,P05)+16C=2P+6H-f  16CO. 

Properties.  —  A  semi-transparent,  colorless,  wax-like 
solid,  which  emits  white  alliaceous  fumes  in  the  air.  Has 
a  sp.  gr.  1.83;  melts  at  111°;  boils  at  550°;  easily 
ignited  ;  very  poisonous ;  its  vapors  produce  necrosis  of 
the  jaw-bone,  and  horrible  suffering  to  workmen  engaged 
in  its  manufacture  ;  exists  in  five  forms.  1st.  The  Trans- 
parent, just  described.  2d.  White ;  formed  by  exposing 
the  first  to  light  under  water,  which  renders  it  opaque, 
and  less  fusible.  3d.  Black,  by  suddenly  cooling  melted 
phosphorus.  4th.  Viscous  ;  suddenly  cooling  phosphorus, 
heated  to  near  its  boiling-point.  5th.  Red,  by  keeping 
phosphorus  for  48  hours,  at  a  temperature  of  about  480°. 
This  variety  does  not  fume,  is  hard  to  ignite,  not  poison- 
ous ;  melts  at  482°,  and  may  be  restored  to  the  trans- 
parent condition  by  heating  to  500°  out  of  contact  with 
air.  Phosphorus  cannot  be  crystallized  by  fusion,  but 
from  its  solution  in  essential  oils,  sulphide  of  phospho- 
rus, and  sulphide  of  carbon,  it  deposits  rhomboidal  dode- 
cahedrons. 

Test.  —  Gives  green  color  to  hydrogen  flame. 

Use.  —  For  friction  matches. 

Compounds  with  Oxygen. 

1st.  Oxide  of  Phosphorus  —  P20.  Formed  in  small 
quantity,  when  oxygen  is  burned  in  air;  a  yellow  powder. 


176  PHOSPHORUS. 

2d.  Hypophosphorous  Acid— PO.     Syrupy  liquid. 

3d.  Phosphorous  Acid  —  PO3.  A  white  deliquescent, 
inflammable  powder. 

4th.  Phosphoric  Acid.  —  P05.  This  is  formed  as  a 
snowy  powder,  when  phosphorus  burns  in  oxygen. 

Use. — Its  intense  avidity  for  water  makes  it  the  best 
desiccating,  or  drying  agent,  known  to  chemists. 

Hydrates  of  Phosphoric  Acid. — Besides  this  anhydride 
of  phosphoric  acid,  three  different  hydrates  of  phosphoric 
acid  are  known : 

1st.  Protohydrate,  or  Metaphosphoric  acid,  HO,P05 . 

2d.  Peutohydrate,  or  Pyrophosphoric  acid,  2  HO,P05 

3d.  Tritohydrate,  or  Tribasic  Phosphoric  acid,  3HO,P05. 

They  are  remarkable  for  forming  with  bases,  three 
entirely  different  classes  of  salts,  containing,  respectively, 
one,  two,  and  three,  equivalents  of  water,  or  a  base. 

Compounds  with  Hydrogen. 

They  are  three  in  number;  viz.  P2H,  PH3,  and  PH2. 
The  first  is  solid ;  the  second  liquid ;  and  the  third  is  a 
gas,  at  ordinary  temperatures ;  the  last  is  the  most  im- 
portant, and  is  known  as 

Phosphuretted  Hydrogen  Gas.  —  It  is  prepared  by  heat- 
ing Phosphorus  with  concentrated  solution  of  caustic 
potassa,  in  a  flask,  carefully  filled  with  these  materials ; 
Hypophosphite  of  Potassa  is  formed  at  the  same  time  ; 
4  P  +  6  HO  -f  3  (KO,HO)  =  3  (KO,PH202)  +  PH3 . 

Properties.  — When  the  gas  so  obtained 
is  allowed  to  escape  into  the  air  through 
the  waters  of  the  pneumatic  trough,  each 
bubble,  as  it  breaks,  takes  fire  sponta- 
neously, and  produces  a  snowy  white 
wreath  of  phosphoric  acid,  which  curls  in- 
ward as  it  ascends. 

Or,  if  fragments  of  Phosphide  of  Calcium 


METALS.  177 

are  thrown  into  a  glass  of  water,  mutual  decomposition 
will  ensue,  the  oxygen  of  the  w^ter  going  to  the  calcium, 
and  the  phosphorus  and  hydrogen  uniting,  and  escaping 
in  bubbles,  which  ignite  as  they  reach  the  air.  (See  Fig. 
144.) 

Combination  with  Iodine.  —  Phosphorus  combines  with 
Iodine  so  readily  that  these  two  bodies  will  unite  in  the 
solid  form,  at  ordinary  temperatures,  with  great  vigor. 
Thus,  if  we  throw  a  few  flakes  of  Iodine  upon  a  bit  of 
Phosphorus,  they  will,  at  once,  combine  igniting  the 
latter. 


METALS. 
Properties  of  the  Metals. 

The  metals  are  mostly  characterized  by  a  peculiar 
brilliancy,  termed  the  metallic  lustre.  This  is  lost,  how- 
ever, when  they  are  finely  powdered,  but  may  be  restored 
by  friction  with  a  hard  body. 

When  in  the  massive  state,  they  are  opaque,  but  if 
reduced  to  leaves  of  excessive  thinness,  they  transmit 
light ;  gold  foil,  for  example,  if  not  more  than  ^ouVfio  ^ncn 
thick,  appears  green  when  held  between  a  bright  light 
and  the  eye. 

Color.  —  Silver,  platinum,  tin,  cadmium,  and  palladium, 
are  almost  white ;  lead  and  zinc  are  blue ;  iron  and 
arsenic,  grey ;  calcium  and  barium,  pale  yellow ;  gold, 
bright  yellow  ;  and  copper,  red. 

Smell  and  Taste.  —  Iron,  tin,  copper,  and  lead,  when 
rubbed  by  the  hand,  emit  a  disagreeable  smell,  peculiar 
to  themselves ;  when  arsenic  is  volatilized,  it  evolves  a 
powerful  odor  of  garlic.  Some  metals,  as  iron,  and  tin, 
have  a  nauseating  metallic  taste. 

Hardness,  Brittleness,  and  Tenacity. — The  hardness  of 


178  METALS. 

the  metals  is  very  variable :  while  potassium  may  be 
moulded  like  wax,  and  lead  may  be  dented  by  the  finger- 
nail, steel  may  be  rendered  hard  enough  to  scratch  steel 
like  the  diamond. 

So  with  regard  to  their  brittleness  and  tenacity.  Some, 
like  antimony,  arsenic,  and  bismuth,  may  easily  be 
crushed  to  powder ;  while  others,  as  gold  and  silver, 
resist  very  great  pressure.  An  iron  wire,  an  inch  thick, 
will  support,  without  breaking,  twice  as  much  as  one  of 
platinum  having  the  same  diameter,  three  times  that  of 
silver,  ten  times  more  than  tin,  and  twenty  times  as  much 
as  zinc. 

Malleability  and  Ductility.  —  The  order  of  malleability, 
by  which  is  meant  the  property  possessed  by  metals  of 
being  rolled  or  hammered  into  leaves,  is  as  follows  :  — 

1.  Gold;  2.  Silver;  3.  Copper;  4.  Tin;  5.  Platinum; 
6.  Lead;  7.  Zinc;  8.  Iron. 

If  the  metals  were  arranged  according  to  their  ductility, 
or  the  ease  with  which  they  are  drawn  into  wire,  the  order 
would  be : — 

1.  Gold;  2.  Silver;  3.  Platinum;  4.  Iron;  5.  Copper; 
6.  Zinc;  7.  Tin;  8.  Lead. 

Their  SPECIFIC  GRAVITY  varies  from  that  of  Lithium, 
0.593,  to  that  of  Platinum,  21.5;  their  FUSIBILITY,  from 
39°,  the  freezing-point  of  mercury,  to  3844°,  the  fusing- 
point  of  forged  iron,  and  even  far  beyond  this,  to  where 
platinum  melts  in  the  oxyhydrogen  flame. 

Chemical  Properties  of  the  Metals. 

Action  of  Oxygen  and  of  Water  on  the  Metals.  —  Potas- 
sium and  Sodium  combine  with  Oxygen,  and  decompose 
water  at  the  ordinary  temperature  ;  Iron,  Lead,  etc.,  only 
when  highly  heated;  and  Gold,  Platinum,  Iridiura,  etc., 
cannot  be  directly  combined  with  Oxygen,  or  be  made  to 
decompose  water  at  any  temperature. 


METALS.  179 

Classification  of  the  Metals,  —  The  metals  are  therefore 
arranged  in  six  groups  :  — 

1.  Metals  of  the  ALKALIES:    Potassium,  Sodium,  Li- 
thium, and  Ammonium. 

2.  Metals  of  the  ALKALINE  EARTHS:   Barium,  Stron- 
tium, Calcium,,  and  Magnesium, 

Termed  alkaline  because  they  have  a  caustic  action 
upon  animal  matters,  and  earths  because  their  oxides  are 
insoluble  in  water. 

3.  Metals  of  the  EARTHS:  Aluminum,  Olucinum,  Zir- 
conium, Thorinum,  Yttrium,  Erbium,  Terbium,  Cerium, 
Lanthanum,  Didymium. 

4.  Metals,  whose  Oxides  form  powerful  BASES  :  Man- 
ganese, Iron,    Chromium,  Nickel,  Cobalt,  Copper,  Zinc, 
Cadmium,  Bismuth,  Lead,  Uranium. 

5.  Metals,  whose  Oxides  form  weak  Bases,  or  ACIDS  : 
Vanadium,  Tungsten,  Molybdenum,  Tantalum,  Niobium, 
Titanium,  Tin,  Antimony,  Arsenic,  Tellurium. 

6.  Noble  Metals.  —  Gold,  Mercury,   Silver,  Platinum, 
Palladium,  Iridium,  Osmium,  Ruthenium,  Rhodium. 

Salts. 

Definitions. — A  salt  is  a  body  formed  by  the  combination 
of  an  acid  with  a  base. 

When  an  oxacid  is  united  with  an  oxygen  base  it  is 
termed  an  oxysalt :  KO-fC02=KO,C02,  Carbonate  of 
'Potash. 

The  union  of  a  Sulphur  acid  with  a  Sulphur  base  gives 
rise  to  a  sulphosalt :  KS4-CS2=KS,CS2,  Sulphocarbonate 
of  Potash. 

When  a  hydracid  unites  with  a  base  it  forms  water  and 
a  binary  compound,  termed  a  haloid  salt:  KO  -f  HCl=a 
KC1  +  HO;  NaO  +  HI=HO  +  NaI;  CaO-f  HF  =CaF-f- 
HO;  H?0  +  HCy=HO+HgCy. 

A  Neutral  Salt  is  one  which  contains  as  many  equiva- 


METALS. 

lents  of  acid  as  there  are  equivalents  of  Oxygen  in  the 
base,  as  CaO,C02,  Carbonate  of  Lime;  Pd02,2S03,  Sul- 
phate of  Binoxide  of  Palladium;  A1203,3S03,  Sulphate  of 
Alumina. 

When  a  neutral  salt  reddens  blue  litmus  paper  it  is 
termed  a  neutral  salt  with  an  acid  reaction,  as  Nitrate  of 
Copper,  CuO,N05. 

If  it  turns  red  litmus-paper  blue  it  is  known  as  a  neu- 
tral salt  with  a  basic  reaction,  as  Carbonate  of  Potash, 
KO,C02. 

An  Acid  Salt  is  one  which  contains  more  equivalents 
of  acid  than  there  are  equivalents  of  Oxygen  in  the  base, 
as  Bichromate  of  Potash,  KO,2Cr03. 

Note.  —  Salts  are  also  termed  monobasic,  bibasic,  and 
tribasic,  according  as  they  are  formed  by  the  union  of  a 
base  with  a  monobasic,  bibasic,  or  tribasic  acid. 

A  Monobasic  Acid  is  one  which  combines  with  but  one 
equivalent  of  a  base,  as  Sulphuric,  Nitric,  etc. 

A  Bibasic  Acid  neutralizes  two  equivalents  of  the  base, 
as  the  Pyrophosphoric,  Tartaric,  Racemic,  and  Gallic 
acids. 

A  Tribasic  Acid  combines  with  three  equivalents  of  the 
base,  as  the  Tannic,  Phosphorous,  Citric  acids,  etc. 

A  Basic  or  Sub-salt  is  one  which  contains  fewer  equiva- 
lents of  acid  than  there  are  equivalents  of  Oxygen  in  the 
base,  as  Sulphate  of  the  Sesquioxide  of  Iron  (Fe203,S03). 

A  Double  Salt  is  one  formed  by  the  combination  of  two 
salts.  The  electro-negative  body  is  usually  the  same  in 
both  salts,  as  KO,S03-f  A1203)3S03-|-24HO,  Alum,  or 
the  double  Sulphate  of  Potash  and  Alumina;  KCl-f- 
PtCl2,  double  Chloride  of  Potassium  and  Platinum ; 
KO,CO  +  HO,CO.,  Bicarbonate,  Super,  or  Acid  Carbo- 
nate of  Potash. 


POTASSIUM.  181 

GROUP  I. 

Sym,  K.  POTASSIUM.  Eq.  39. 

Isolated  by  Davy,  in  1807,  from  moistened  Hydrate  of 
potassa  placed  in  contact  with  the  poles  of  a  very  power- 
ful galvanic  battery. 

Preparation. — When  Carbonate  of  Potassa  and  charcoal 
are  intimately  mixed  together  and  subjected  to  intense 
heat,  carbonic  oxide  and  potassium  vapor  are  set  free. 
The  latter  is  solidified  by  cold,  and  collected  in  a  proper 
receiver,  KO,C02-f  2C=K  +  3CO. 

Properties. — A  bluish-white  metal,  which  is  brittle  and 
crystalline  at  32°,  soft  at  60°,  liquid  at  130°.  Its  specific 
gravity  being  only  0.865,  Potassium  will  float  upon  water. 
Enters  directly  into  combination  with  the  halogens,  and 
with  Sulphur,  Selenium  and  Tellurium,  burning  vividly 
when  heated  with  them.  So  strong  is  its  affinity  for  oxy- 
gen that  it  cannot  be  preserved  in  the  open  air,  but  only 
in  a  vacuum,  or  under  the  surface  of  some  liquid,  like 
Naphtha,  which  does  not  contain  oxygen.  When  a  lump 
of  Potassium  is  thrown  upon  water,  it  is  constantly  tossed 
up  from  the  surface  and  kept  dancing  about  by  the  hydro- 
gen set  free  from  the  rapidly  decomposed  water.  It  grows 
at  the  same  time  red  hot,  from  its  fierce  union  with  the 
liberated  hydrogen  to  form  Potash.  Reduces  many  oxides 
when  heated  in  contact  with  them. 

Compounds  with  Oxygen. 

Teroxide  of  Potassa — K03.  Formed  when  potassium 
is  heated  in  an  excess  of  dry  oxygen  gas. 

Potassa — KO.  Generated  by  the  oxidation  of  potassium 
in  dry  air.  Known  in  chemistry  as  a  reagent  only  in  the 
form  of  HYDRATE  OF  POTASSA,  KO,HO. 

Sources. — Found  combined  with  Silica  in  Mica  and  Fel- 
16 


182  POTASSIUM. 

spar.  By  decomposition  of  these  two  minerals,  it  passes 
into  the  soil.  The  fertility  of  land  depends  in  great  mea- 
sure upon  the  quantity  of  Potassa  which  it  contains. 
From  the  earth  it  is  taken  up  by  plants,  and  it  is  from  the 
ashes  of  burnt  trees  that  the  carbonate  of  potash,  or  pearl- 
ash  of  commerce,  is  obtained. 

Preparation. — This  hydrate  is  manufactured  by  dissolv- 
ing Carbonate  of  Potassa  in  10  or  12  times  its  weight  of 
water,  and  adding  to  the  boiling  solution  a  quantity  of 
caustic  lime,  equal  in  weight  to  half  the  Carbonate  of 
Potassa  used,  KO,C02+CaO,HO=KO,HO  +  CaO,C02. 

Uses. — The  glass  maker  unites  it  with  sand  to  make 
Silicate  of  Potassa,  one  of  the  components  of  glass ;  the 
soap-maker  unites  it  with  a  fatty  acid  to  form  soft  soap : 
the  chemist  absorbs  carbonic  acid  with  it,  and  decomposes 
by  it  all  those  metallic  salts,  the  bases  of  which  are  insol- 
uble in  water.  It  is  very  alkaline,  and  unctuous  to  the 
touch  ;  it  instantly  alters,  and  finally  destroys  the  skin, 
for  which  reason  it  is  employed  as  an  escharotic,  under 
the  name  of  caustic  potash.  Ignited  with  the  insoluble 
silicates,  it  renders  them  soluble  in  acids :  this  operation 
must  be  performed  in  silver  or  platinum  capsules. 

Compounds  with  the  Halogens. 

Chloride  of  Potassium,  KC1,  is  extracted  from  kelp,  the 
ashes  of  burnt  sea-weeds.  It  is  used  in  large  quantities, 
as  a  source  of  potassa  in  alum  manufacture.  The  slaty 
clay  which  is  used  for  making  alum  is  filled  with  bisul- 
phide of  iron,  FeS2;  hence,  on  roasting,  sulphate  of  the 
protoxide  of  iron  and  sulphate  of  alumina  are  formed. 
But  alum  is  a  double  sulphate  of  potassa  and  alumina. 
Chloride  of  potassium  is  therefore  employed  to  decompose 
the  sulphate  of  iron:  FeO,S03+Al203,3S03+KCl-f  Aq= 
(KO,S03+Al2O3,3S03+24HO)  +  FeCl. 

Also,  to  effect  the  decomposition  of  nitrate  of  lime  in 


POTASSIUM.  183 


one  mode  of  manufacturing  saltpetre:  CaO^Og-l-  KC1= 
KO,N06+CaCl. 

Iodide  of  Potassium,  KI,  is  procured  by  digesting  2 
parts  of  iodine  and  1  of  iron  in  10  parts  of  water;  the  pro- 
tiodide  of  iron  so  formed  is  afterwards  converted  into 
iodide  of  potassium  by  carbonate  of  potassa:  Ee  +  I= 
Pel  and  FeI+KO,C02=KI+FeO,C02. 

Uses.  —  In  the  manufacture  of  the  metallic  iodides  ;  to 
dissolve  the  Iodide  of  Silver  employed  in  iodizing  photo- 
graphic paper,  and  as  a  remedy  for  cutaneous  disorders. 

Compounds  with  Acids.    Fotassa  Salts. 

Carbonate  of  Potassa  —  KO,C02.  In  commerce  called 
Vegetable  Alkali,  Salt  of  Tartar,  Dulcified  Alkali,  Pearl- 
ash,  or  simply  Potash. 

Preparation.  —  Potassa,  KO,  exists  in  large  quantities 
in  plants,  combined  with  various  organic  acids,  such  as 
Malic,  Acetic,  Oxalic,  Tartaric,  etc.  These  salts  are  all 
converted,  by  burning,  into  Carbonates  of  Potassa,  and  the 
latter  may  therefore  be  obtained  by  making  a  lye  of  wood- 
ashes,  and  evaporating  until  the  carbonate  of  potassa 
crystallizes  out.  Birch-ash  yields  the  purest  potash,  pine 
ashes  the  least  ;  herbaceous  plants  furnish  more  than 
shrubs,  and  shrubs  more  than  timber;  the  quantity 
afforded  by  the  leaves  is  to  that  procured  from  heartwood 
as  25  to  1. 

Uses.  —  In  the  manufacture  of  soft  soaps,  crystal  glass, 
Prussian  blue,  and  sometimes  to  decompose  the  nitrates 
of  lime  and  magnesia,  employed  in  making  saltpetre. 
When  changed  to  the  bicarbonate  or  sal  aeratus  (KO,C02 
-J-HO,CO2),  by  passing  a  current  of  Carbonic  acid  through 
a  solution  of  the  carbonate,  it  is  used  in  the  treatment  of 
gout  and  gravel,  and  mixed  with  citric  or  tartaric  acid,  to 
make  effervescing  draughts. 

Sulphate  of  Potassa,  KO,S03,  obtained  by  neutralizing 


184  POTASSIUM. 

the  Bisulphate  of  Potassa  (KO,S03+HO,S03),  which  is 
left  as  a  residue  in  the  manufacture  of  Nitric  acid  with 
KX),C02,  is  used  as  a  gentle  laxative.  In  analysis,  the 
former  salt  serves  to  detect  and  separate  baryta  and 
strontia ;  the  latter  as  a  flux  for  salts,  or  metallic  oxides, 
which  are  required  to  be  acted  upon  by  an  acid  at  a  high 
temperature. 

Nitrate  of  Potassa  —  KO,N05.  Salt  of  Nitre,  Nitre, 
Saltpetre. 

Source.  —  Formed  abundantly  in  the  hot  weather  suc- 
ceeding rain-storms,  in  certain  soils  of  Spain,  Egypt,  Per- 
sia, and  the  East  Indies,  which  are  rich  in  potash.  (See 
AMMONIA.)  Incrusts  the  interiors  of  many  caverns  in  the 
West,  and  in  Ceylon.  Artificially  prepared  by  the  oxida- 
tion of  ammonia  in  the  presence  of  a  powerful  base  in 
nitre  plantations ;  animal  refuse  of  all  kinds,  the  cleaning 
of  sinks,  stables,  etc.,  are  thrown  together  with  old  mor- 
tar, plaster  from  ceilings,  etc.,  into  great  heaps.  After 
three  years  these  nitre  beds  are  washed,  and  yield  to 
every  cubic  foot  4  and  5  ounces  of  nitre. 

This  salt  crystallizes  in  the  form 
Fig.  145.  Of  an  hexagonal  prism.     A  slice  of 

this,  cut  perpendicular  to  its  axis, 
viewed  between  two  polarizing 
bodies,  as  in  Fig.  54,  or  55,  shows 
the  system  of  colored  rings  and  dark 
brushes,  indicated  in  Fig.  60,  when 
the  plane  of  its  two  optical  axes  co- 
incides with  the  plane  of  the  polar- 
izer, and  the  system  represented  in 
Fig.  145,  when  these  planes  are 
slightly  inclined. 

Uses. Nitre  is  extremely  valuable  on  account  of  the 

facility  with  which  it  yields  up  its  oxygen.  It  is  con- 
stantly employed  to  oxidize  the  metallic  sulphides  into 


POTASSIUM.  185 

sulphates,  carbon  into  carbonic  acid,  etc.  Ex.  Rapid  com- 
bustion (deflagration)  of  a  mixture  of  carbon  and  nitre,  or 
of  sulphide  of  antimony  (SbS3),  or  sulphur  with  nitre,  when 
touched  by  an  incandescent  body.  This  property  of  nitre 
gives  it  wonderful  adaptation  for  its  use  in 

Gunpowder. — Gunpowder,  used  in  France,  Prussia,  and 
the  United  States  in  war,  consists  of  75  parts  of  saltpetre, 
12 2  parts  of  charcoal,  and  12?  parts  of  sulphur.  The  salt- 
petre starts  the  detonation  by  giving  up  all  its  Oxygen  to 
the  Carbon  to  form  Carbonic  oxide  and  Carbonic  acid 
gases,  the  Potassium  and  Nitrogen  being  thus  set  free. 
The  former  straightway  seizes  upon  the  Sulphur  to  form 
vaporous  Bisulphide  of  Potassium,  the  latter  flies  off 
as  gas :  KO,N05  +  S2  +•  4C  =  KS2  -f  2CO  -f  2C02  -f  N. 
The  temperature  at  the  moment  of  explosion  rises  to 
2200°,  high  enough  to  melt  gold  and  copper  coin ;  and 
dilates  the  liberated  gases,  already  occupying  an  enor- 
mous volume,  until  an  amount  of  powder  which  filled  1 
cubic  foot  of  the  gun,  after  firing,  expands  to  2000  cubic 
feet. 

East  Indiamen  prepare  cooling  drinks  from  nitre; 
butchers  employ  it  to  preserve  meats;  physicians  as  a 
diuretic,  and  for  asthma.  Lucifer  matches  are  made 
from  it. 

Chlorate  of  Potash  — KO,C105.  Largely  manufactured 
by  passing  Chlorine  through  a  thin  cream  of  1  part  of 
Chloride  of  Potassium  and  2  parts  of  Hydrate  of  Lime 
dissolved  in  water:  KC1  +  CaO  -f  6C1  =  KO,ClOfi  -f 
GCaCl.  Ex.  Rubbed  with  charcoal,  sulphur,  and  phos- 
phorus the  mixture  explodes,  in  consequence  of  the  rapid 
oxidation  of  these  bodies  by  the  Chlorate. 

Uses. — By  the  chemist  and  calico-printer  as  an  oxidizing 

agent ;  in  lucifer  matches ;  and  in  percussion  powder  for 

gun-caps.    The  friction  tubes  for  cannon-firing  are  charged 

with  a  mixture  of  2  parts  of  Chlorate  of  Potash,  2  of  Sul- 

16* 


186  SODIUM. 

phide  of  Antimony,  and  1  of  powdered  glass.  A  mixture 
of  Chlorate  of  Potash,  dried  Ferrocyanide  of  Potassium 
and  Sugar  has  been  used  for  blasting,  under  the  name  of 
white  gunpowder;  but  the  ease  with  which  it  explodes  by 
friction  has  rendered  its  manufacture  fatal  to  many. 

Test. — When  a  strong  solution  of  Bichloride  of  Plati- 
num is  poured  into  a  concentrated  solution  of  a  potash 
salt,  a  yellow  double  Chloride  of  Potassium  and  Platinum 
(KC1  +  PtClj)  precipitates. 


Sym.  Na.  SODIUM.  Eq.  23. 

Discovered  by  Davy  in  1807,  and  obtained  by  him  in  the 
same  manner  as  Potassium.  Prepared  like  Potassium  for 
commercial  uses. 

Properties. — A  bluish-white  metal ;  soft  at  common  tem- 
peratures, melts  at  194°.  Decomposes  cold  water  with 
the  evolution  of  heat  but  not  of  light.  The  Oxide,  Sul- 
phides, and  Haloids  of  Sodium  correspond  in  properties 
and  mode  of  formation  with  those  of  Potassium.  Sp.  Gr. 
0.972. 

Chloride  of  Sodium — TsTaCl.    Sea  Mineral,  or  Rock  Salt. 

Sources. —  Found  in  Poland,  England,  Spain,  and  other 
places  as  a  rocky  deposit,  often  of  great  thickness  and 
extent.  Obtained  likewise  by  evaporating  in  salt-pans  the 
waters  of  the  ocean,  and  those  pumped  from  the  salt-wells 
of  Western  Virginia  and  Pennsylvania. 

Uses. — To  season  food  ;  in  the  manufacture  of  Sulphate 
and  Carbonate  of  Soda,  of  Hydrochloric  acid,  the  bleach- 
ing Chlorides,  and  Chlorine ;  in  forming  salt-glaze  upon 
pottery  ;  in  manufacturing  soap  ;  in  preserving  meat. 

Sulphate  Of  Soda,  NaO,S03,  is  manufactured  on  a  vast 
scale  in  Leblanc's  process  for  making  Carbonate  of  Soda, 
by  causing  Sulphuric  acid  to  react  upon  common  salt; 
thus;  NaCl-f  HO,S03=NaO,S03+HCl.  It  was  for- 
merlv  also  in  favorite  use  as  a  saline  cathartic,  under  the 


SODIUM.  187 

name  of  Glauber's  salt,  but  it  has  gradually  been  replaced 
by  Sulphate  of  Magnesia. 

Carbonate  of  Soda,  NaO,C02,  is  prepared  by  throwing 
into  an  elliptical  reverberatory  furnace  1000  Ibs.  of  salt 
cake,  or  Anhydrous  Sulphate  of  Soda,  obtained  by  the 
above  reaction,  intimately  mixed  with  1000  Ibs.  of  dry 
chalk,  and  350  Ibs.  of  crushed  coal.  The  Sulphate  of  Soda 
is  reduced  by  the  coal  to  Sulphide  of  Sodium,  NaO,SO  -f- 
40  =NaS  -f  4CO;  and  this  Sulphide  effects  a  double  de- 
composition of  the  Carbonate  of  Lime,  to  form  Carbonate 
of  Soda  and  Sulphide  of  Calcium,  NaS  +  CaO,C02  = 
NaO,CO2  -f  CaS.  Fifteen  hundred  pounds  of  this  crude 
artificial  soda  or  black  ash  may  be  obtained  from  the  pre- 
ceding charge.  Crystallized  from  its  solution,  it  is  known 
in  commerce  as  sal  soda. 

Uses.  —  The  soap-makers  use  vast  quantities  of  black 
ash  to  make  from  it,  by  treatment  with  milk  of  lime,  their 
caustic  Soda,  or  Soda  lye,  employed  in  the  manufacture 
of  hard  soap :  NaO,C02  -f  CaO,HO  =  NaO,HO  +  CaO, 
C02.  Used  as  a  detergent  by  the  calico-printer,  and, 
under  the  name  of  washing  soda,  in  the  kitchen.  It 
unites  with  the  grease  in  the  dirty  linen,  and  forms  with 
it  a  kind  of  soap.  In  the  laundry  for  softening  hard 
waters,  by  forming  with  the  soluble  salts  of  Lime  and 
Magnesia  insoluble  Carbonates.  In  the  manufacture  of 
glass.  Treated  with  excess  of  Carbonic  acid  it  is  con- 
verted into  Bicarbonate  or  Supercarbonate  of  Soda  (NaO, 
C02  -f  HO,C02).  It  is  mixed  with  Rochelle  salt  in  the 
blue  paper  which  is  sold,  along  with  a  white  envelope 
enclosing  Tartaric  acid,  by  druggists,  as  Seidlitz  powders. 

Phosphates  of  Soda, 

Phosphoric  Acid  forms  with  Soda  several  crystallizable 
salts,  which  differ  from  each  other  in  the  number  of  equiva- 
lents of  Soda  united  with  one  equivalent  of  the  acid,  viz. : 


188  SODIUM. 

(a)  The  Tribasic  Phosphates  of  Soda,  which  are  three 
in  number :  — 

1st.  Neutral  Tribasic  Phosphate,  or  Subphosphate  of 
Soda  (3NaO,P05+24Aq). 

2nd.  JRhombic  Phosphate  of  Soda,  (2NaO,HO,P05  + 
24Aq).  From  this  salt  all  the  other  Phosphates  of  Soda 
are  formed.  It  has  been  longest  known,  and  is  familiar 
under  the  name  of  Commercial  Phosphate  of  Soda. 

3rd.  Biphosphate  of  Soda,  (2HO,NaO,P05  +  24Aq). 

Test.  —  These  three  tribasic  phosphates  give  with  Ni- 
trate of  Silver  a  yellow  precipitate.  They  always  require 
three  equivalents  of  the  salt,  with  which  they  react :  thus, 

3NuO,P05        >)  /-3(NaO,N05) 

2NaO,HO,P05  t  +  3(AgO,N03)  =  3AgO,P05+  ]  2(NaO,N05)  +  HO,N05) 
2HO,NaO,P05  J  (  NaO,N05+2(HO,N05) 

(6)  Pyrophosphate  of  Soda  (2NaO,P05-f  lOAq). 
Test. — Gives  a  dense  white  precipitate  with  Nitrate  of 
Silver.    Reacts  with  two  equivalents  of  another  salt :  thus, 

2NaO,P05+2(AgO,N05)=2AgO,P03-f2(NaO,N05). 

(c)  Metaphosphate  of  Soda  (NaO,P05). 

Test.  —  Gives  a  gelatinous  white  precipitate  with  Ni- 
trate of  Silver.  Reacts  with  one  equivalent  of  another 
salt:  NaO,P05  +  AgO,N05=AgO,P05+NaO,N05. 

tT-ges.— Phosphate  of  Soda  (2NaO,HO,P05)  precipitates 
all  the  alkaline  earths  and  metallic  oxides.  After  the 
oxides  of  the  heavy  metals  have  been  separated,  it  serves 
in  analysis  as  a  test  for  the  alkaline  earths  in  general ; 
and  after  the  separation  of  Baryta,  Strontia,  and  Lime  it  is 
used,  in  conjunction  with  Ammonia,  to  precipitate  Mag- 
nesia, as  the  basic  Phosphate  of  Magnesia  and  Ammonia 
(NH40,MgO,HO,PO5).  Combined  with  Ammonia  as  mi- 
crocosmic  salt  (NaO,NH40,HO,P05),  it  is  frequently  pre- 
ferred to  Borax  as  a  flux  before  the  blowpipe,  because  with 
many  substances  it  gives  a  more  brilliantly  colored  bead. 


LITHIUM,  189 

Biborate  of  Soda— NaO,2B03+lOAq.    Borax. 

Sources.  —  For  many  years  the  crude  Borax,  or  Tincal 
of  commerce,  was  obtained  by  evaporation  of  the  waters 
of  certain  lakes  in  Thibet.  Now  manufactured  from  the 
Boracic  acid  present  in  the  lagunes  of  Tuscany,  by  neu- 
tralizing it  with  Carbonate  of  Soda,  and  allowing  the  satu- 
rated solution  to  crystallize. 

Uses. — When  two  oxidizable  metals,  such  as  Copper  and 
Iron,  are  to  be  soldered  together,  the  brazier  sprinkles  their 
surfaces  with  Borax.  This  dissolves  off  the  oxide,  which 
would  otherwise  prevent  their  union,  as  fast  as  it  is 
formed.  The  goldsmith  also  employs  it,  in  both  refining 
and  soldering  the  precious  metals.  It  enters  into  enamels 
to  render  them  more  fusible,  and  into  the  composition  of 
easily  melted  glasses  ;  it  is  employed  in  fixing  colors  upon 
porcelain,  and  for  the  glazing  of  some  potteries.  The  free 
Boracic  acid,  which  is  present  in  Borax,  along  with  the 
Borate  of  Soda  (commonly  called  Biborate  of  Soda),  has 
an  earnest  affinity  for  metallic  oxides  at  high  temperatures. 
It  consequently  forms  with  them  and  the  Borate  of  Soda 
before  the  blowpipe  double  borates,  which  have  different 
colors,  and  which  serve  to  detect  the  different  metals  ; 
with  Oxide  of  Chromium,  emerald  green;  with  Oxide  of 
Cobalt,  a  deep  blue ;  with  Oxide  of  Copper,  a  pale  green; 
with  Oxide  of  Tin,  an  opal ;  with  Oxide  of  Manganese,  a 
violet,  etc. 


Sym.  L.  LITHIUM.  Eq.  7. 

Isolated  by  Davy  by  means  of  the  galvanic  battery,  and 
named  from  xi'0o$,  a  stone,  because  it  is  found  only  in  the 
minerals,  lepidolite,  spodumene,  and  petalite. 

Properties.  — A  white  metal,  fusible  at  356°,  and  burn- 
ing with  a  brilliant  white  light.  It  is  the  lightest  of 
solids.  Sp.  Gr.  0.5936. 


190  AMMONIUM. 

Tests. — A  purplish  red  color  in  the  blowpipe  flame,  and 
one  intensely  bright  red  band  in  the  spectroscope. 


Sym.  NH4,  or  Am.  AMMONIUM  (hypothetical).         Eq.  18. 

Ammoniacal  Amalgam.  —  Ammonium  has  never  been 
isolated,  but  is  thought  to  exist  in  combination  with  Mer- 
cury in  the  compound  which  is  formed  when  a  concen- 
trated solution  of  Sal  Ammoniac  is  poured  upon  Sodium 
Amalgam.  The  latter  increases  in  bulk  to  10  times  its 
original  volume,  and  acquires  a  pasty  consistence,  but 
nevertheless  preserves  its  metallic  lustre.  On  applying 
heat,  Hydrogen  and  Ammonia  are  rapidly  given  off,  and 
pure  Mercury  left  behind,  From  the  character  of  its  salts, 
Ammonium  is  placed  among  the  alkaline  metals. 

Oxide  of  Ammonium — NH40.  Ammonia.  When  Ammo- 
nia, NH3,  enters  into  combination  with  anhydrous  Sulphu- 
ric acid,  S03,  it  forms,  not  the  ordinary  salt,  Sulphate  of 
Ammonia,  but  a  sulphate  of  very  different  properties.  It- 
is  only  when  the  hydrated  acid,  HO,S03,  is  combined  with 
Ammonia  that  the  regular  Sulphate  of  Ammonia  is  formed. 
Therefore  the  basic  water  of  the  acid  must  have  united 
with  the  gaseous  Ammonia  to  form  a  new  base,  and  this 
new  base  is  what  we  shall  henceforth  regard  as  Ammonia, 
NH40:  thus,  NH3  +  HO,S03=NH4O,S03. 

Chloride  of  Ammonium,  Muriate  of  Ammonia,  Sal  am- 
moniac—  NH4,C1.  The  foregoing  theory  is  strengthened 
by  the  fact,  that  when  dry  Hydrochloric  acid  is  mixed 
with  dry  Ammoniacal  gas,  a  white  solid  is  formed  which 
is  ordinary  Sal  Ammoniac,  and  that  this  Sal  Ammoniac,  if 
dissolved  in  water,  gives  with  Nitrate  of  Silver  the  same 
curdy  precipitate  as  is  formed  when  any  other  chloride 
reacts  with  Nitrate  of  Silver:  that  is  to  say,  Sal  Ammo- 


AMMONIUM.  191 

niac  is  not  Hydrochlorate  of  Ammonia,  NH3HC1,  but 
Chloride  of  Ammonium,  HH4C1. 

Sources. — It  derives  its  name  from  Ammon,  the  ancient 
appellation  of  Egypt,  where  it  was  originally  manufac- 
tured by  the  dry  distillation  of  camel's  dung.  It  was  also 
termed  Spirit  of  Hartshorn,  because  obtained  from  horn- 
shavings  by  heat.  Now  manufactured  by  neutralizing, 
with  hydrochloric  acid,  ammoniacal  liquor,  or  water  laden 
with  ammoniacal  salts,  tar,  and  other  impurities  taken  up 
in  washing  coal-gas. 

Uses.  —  Owing  to  its  great  solubility  and  the  resulting 
depression  of  temperature,  it  is  used  in  freezing  mixtures; 
in  the  preparation  of  the  sesquicarbonate  of  ammonia 
(2NH40,3C02),  or  smelling-salts  of  the  shops.  To  re- 
move rust  from  metals,  particularly  copper;  in  dyeing;  in 
preference  to  chloride  of  sodium  and  chloride  of  barium  for 
salting  photographic  paper  ;  it  is  sprinkled  over  iron-filings 
previously  mixed  with  one  hundredth  part  of  sulphur,  to 
form  a  lute  for  cementing  iron  into  stone.  A  mixture  of 
the  chlorides  of  silver  and  ammonium  is  sometimes  em- 
ployed for  silvering  copper  and  brass  without  heat. 

Uses  of  other  Ammoniacal  Salts. 

Carbonate  of  Ammonia,  NH40,C02,  is  preferred,  in  con- 
sequence of  its  volatility  on  heating,  to  the  carbonate  of 
soda  for  precipitating  the  metallic  oxides  and  earths.  It 
is  principally  employed  to  separate  the  alkaline  earths  from 
magnesia,  and  to  separate  also  sulphide  of  arsenic,  which 
is  soluble  in  it,  from  sulphide  of  antimony  which  is  in- 
soluble. Molybdate  of  Ammonia,  MH4O,Mo03,  when 
added  in  great  excess  to  their  acid  salts,  serves  to  detect 
the  faintest  trace  of  phosphoric  and  arsenic  acids.  Oxalate 
of  Ammonia,  NH40,C203,  is  a  most  delicate  test  of 
lime,  precipitating  it  as  an  oxalate,  CaO,S03  +  NH40,C203 
=  CaO,C203  +  NH40,S03.  Hydrosulphate  of  Ammonia, 


192  BARIUM. 

NH4S,HS,  is  employed  to  detect  many  of  the  metals  by 
precipitating  them  as  differently  colored  sulphides,  and  is 
used  like  sulphide  of  potassium  for  bronzing  electro-plated 
medals. 

GROUP  II. 

Metals  of  the  Alkaline  Earths, 
Sym.  Ba.  BARIUM.  Eq,  68,5. 

History. —  Obtained  by  Davy,  in  1808,  from  moistened 
carbonate  of  baryta  in  contact  with  mercury,  when  the 
latter  was  made  the  positive  pole  of  a  powerful  galvanic 
battery.  It  may  also  be  procured  by  passing  potassium 
vapor  over  baryta  heated  to  redness  in  an  iron  tube.  De- 
rives its  name  from  |3apv?,  heavy,  owing  to  the  great  weight 
of  its  compound. 

Properties.  —  A  white  metal,  fusible  under  a  red  heat. 
Decomposes  water  with  rapid  evolution  of  hydrogen. 

Baryta,  BaO,  exists  as  a  sulphate,  heavy  spar,  and  as 
a  carbonate,  witherite,  which  often  constitute  the  vein- 
stone or  gangue  in  mines.  Obtained  by  calcination  of 
nitrate  of  baryta.  When  heated  to  redness  in  an  atmos- 
phere of  oxygen,  it  is  converted  into  the  binoxide  which  is 
interesting  as  the  source  of  binoxide  of  hydrogen. 

Uses. — Hydrated  baryta,  BaO, HO,  and  also  the  Chlo- 
ride of  barium,  BaCl,  and  Nitrate  of  baryta,  BaO,NO5, 
are  employed  to  precipitate  Sulphuric  acid  by  forming  with 
it,  even  in  very  dilute  solutions,  an  insoluble  Sulphate  of 
baryta,  BaO,S03.  Fifty  grains  of  nitrate  of  baryta  mixed 
with  150  of  sulphur,  100  of  chlorate  of  potassa,  and  25  of 
lampblack,  constitute  the  "green-fire,"  of  the  pyrotechnist. 

As  a  carbonate,  BaO,C02,  it  is  employed  in  the  analy- 
sis of  siliceous  minerals,  which  are  insoluble  in  acids, 
forming  when  fused  with  them  a  silicate  of  baryta,  and  a 
soluble  carbonate  of  the  mineral  oxide  to  be  determined. 


STRONTIUM.  193 

The  sulphate  (BaO,S03)  is  the  permanent  white  of  water- 
color  artists;  it  is  also  employed  to  adulterate  white  lead. 
When  mingled  in  excess  with  this  latter  pigment  it  forms 
Dutch  white ;  in  equal  amount,  Hamburg,  and  in  lesser 
quantity,  Venice  white.  But  it  becomes,  when  ground 
with  oil,  translucent,  and  impairs  the  opacity  of  the  lead 
paint. 

Character  of  the  Salts. — Colorless  and  poisonous,  the 
best  antidote  being  Epsom  salts.  Give  a  white  precipitate 
with  sulphuric  acid,  which  is  insoluble  in  acids. 


Sym.  Sr.  STRONTIUM.  Eq.  43.84. 

Discovered  by  Davy,  at  the  same  time  and  in  the  same 
way  as  Barium,  which  it  closely  resembles  in  properties. 
It  is  found  native  as  a  carbonate,  strontianite,  and  as  a 
sulphate,  celesfine  ;  from  the  former,  which  was  first  found 
at  the  mining  village  of  Strontian,  in  Scotland,  it  derives 
its  name.  All  the  salts  of  strontia  are  distinguished  by 
the  crimson  tinge  which  they  impart  to  the  blowpipe 
flame  ;  and  "  red-fire  "  is  made  by  mixing  40  drachms  of 
dry  Nitrate  of  Strontia  (SrO,N05),  with  10  of  Chlorate  of 
Potassa,  13  of  Sulphur,  and  4  of  Sulphide  of  Antimony. 

Sym.  Ca.  CALCIUM.  Eq.  20. 

Isolated  by  Davy,  in  1808,  with  the  galvanic  battery, 
from  moist  lime. 

Properties. — As  obtained  by  the  fusion  of  sodium  with 
iodide  of  calcium  (Cal  +  Na  =  Ca  +  Nal),  it  is  a  light 
yellow  metal,  which  is  very  malleable,  and  which  slowly 
decomposes  water  at  ordinary  temperatures.  It  enters 
into  combination  with  oxygen,  chlorine,  bromine,  iodine, 
and  sulphur,  when  heated  with  them ;  the  union  being 
accompanied  by  vivid  light.  Sp.  Gr.  1.518. 

Lime — CaO.  Caustic,  or  Quicklime,  is  obtained  by 
burning  lime  in  kilns  having  the  form  of  a  cone,  inverted 
17 


194  /  CALCIUM 


. 


. 

and  truncated.  Four  parts  of  coal  and  one  of  lime  having 
been  thrown  in  from  above,  the  fire  is  lighted  by  means 
of  fagots  and  gradually  spreads  throughout  the  kiln.  As 
fast  as  the  carbonic  acid  has  been  driven  off,  the  lime  is 
removed  by  openings  at  the  base  of  the  kiln,  while  fresh 
layers  of  carbonate  of  lime  and  coal  are  added  at  the  top. 

Uses.  —  When  the  oxyhydrogen  flame  is  turned  upon 
cylinders  of  quicklime,  it  causes  them  to  glow  with  the 
intense  brilliancy  known  as  the  Drummond  Light.  Mixed 
with  water,  a  hydrate  of  lime,  which  is  commonly  known 
as  slaked  lime  (CaO,HO),  is  formed.  The  latter  has  the 
power  of  uniting  with  the  carbonic  acid  which  is  present 
in  the  atmosphere,  and  forming  with  it  a  solid  carbonate 
of  lime.  Hence  its  utility,  when  stiffened  with  sand,  in 
mortars  and  cements. 

Lime  is  also  employed  to  loosen  hair  from  hides  in  tan- 
ning ;  to  purify  coal-gas,  by  absorbing  from  it  sulphuretted 
hydrogen  and  carbonic  acid  ;  to  set  free  the  stearic  acid 
used  for  candles,  from  the  fatty  base  ;  to  defecate  sugars, 
or  to  remove  the  acetic  and  lactic  acids  present  in  the  raw 
syrup,  by  forming  with  them  insoluble  acetates  and  lac- 
tates.  It  acts  as  a  manure,  by  decomposing  the  organic 
matter  which  is  present  in  the  soil,  and  making  it  soluble 
in  water.  One  ounce  of  lime  is  soluble  in  about  700  ounces 
of  water  ;  and  its  solution,  which  is  known  as  lime-water, 
is  valuable  as  a  test  for  carbonic  acid,  in  consequence  of 
the  turbidity  arising  from  the  faintest  trace  of  the  latter. 

When  a  stream  of  chlorine  is  passed  over  masses  of 
slaked  lime,  a  mixture  of  Chloride  of  calcium  and  Hypo- 
chlorite  of  lime  is  formed,  which  is  familiarly  known  as 
Chloride  of  lime  or  Ble  aching-powder  :  2CaO  -f  201  = 
CaCl  -f  CaO,C10. 

The  Chloride  of  Calcium,  CaCl,  alluded  to  above,  has  an 
intense  avidity  for  moisture;  and  it  is  therefore  used  in 
the  drying  or  desiccation  of  gases. 


CALCIUM.  195 

Carbonate  of  Lime,  CaO,Co2,  in  the  amorphous  condi- 
tion, constitutes  the  different  varieties  of  limestone,  oolite, 
chalk,  alabaster,  and  lithographic  stone.  Crystallized  in 
rhombohedra,  it  is  distinguished  as  calcite  and  Iceland  spar. 
Sections  of  this,  as  described  on  page  6T, 
show,  with  polarizing  instruments,  colored 
rings  and  crosses,  as  represented  in  Fig. 
5T,  and  Fig.  146 ;  the  first  with  the  polar- 
izer and  analizer  lt  crossed,"  the  last  with 
these  parallel.  In  six-sided  prisms, 
CaO,C02  occurs  as  aragonite  ;  in  minute 
granular  crystals,  as  marble  in  its  endless 
forms.  It  enters  largely  into  the  bony  structure  of  men 
and  animals,  and  is  the  chief  component  of  corals  and  of 
shells.  It  is  soluble  in  water  containing  carbonic  acid ; 
and  when  the  latter  is  driven  off  by  heat  or  in  any  other 
way,  it  is  again  deposited.  In  this  manner  are  formed 
the  incrustations  on  the  sides  of  steam  boilers,  which  so 
frequently  lead  to  explosions;  and  the  stalactites,  which 
depend  from  the  ceiling,  and  the  stalagmites,  that  rise  from 
the  floor,  of  caverns  in  limestone  districts. 

Sulphate  of  Lime  —  CaO,S03-f  2HO.  Gypsum  is  es- 
pecially valuable  as  affording  a  powder  known  as  Plaster 
of  Paris,  when  its  water  of  cystallization  has  been  driven 
off  by  a  heat  not  exceeding  500°.  This  plaster  has  the 
singular  property  of  expanding,  when  made  into  a  paste 
with  water,  and  then,  in  the  course  of  a  few  minutes,  of 
setting,  or  changing  to  a  solid  mass.  It  is  therefore  largely 
employed  for  copying  medals,  busts,  statues,  for  moulds 
in  stereotyping,  etc.,  and  as  cement,  stucco,  etc. 

Tribasic  Phosphate  of  Lime,  3CaO,P05,  forms  more 
than  half  of  the  bones  of  men  and  other  animals.  When 
converted  to  the  acid,  or  superphosphate  of  lime  (CaO, 
2HO,P05),  by  heating  with  two-thirds  its  weight  of  sul- 
phuric acid,  it  is  largely  employed  in  the  manufacture  of 
phosphorus,  and  as  a  manure  for  turnips. 


196 


MAGNESIUM. 


Character  of  Lime  Salts. — They  are  all  colorless,  and 
afford,  with  oxalate  of  ammonia,  a  copious  precipitate  of 
oxalate  of  lime,  CaO,C203  +  2HO. 


Sym.  Mg.  MAGNESIUM.  Eq.  12. 

Discovered  by  Bussy,  in  1828. 

It  is  prepared  by  heating  the  anhydrous  double  Chloride 
of  Magnesium  and  Sodium  with  metallic  Sodium.  The 
process  for  manufacturing  on  the  large  scale  was  patented 
and  is  carried  on  in  England  by  Sonstadt;  in  this  country 
it  is  made  under  the  same  patent  by  the  American  Mag- 
nesium Company,  Boston,  Massachusetts.  (See  Journal 
of  Franklin  Institute,  Vol.  50. 

Sources.  —  Combined  with  carbonic  acid,  as  a  double 
carbonate  of  lime  and  magnesia,  forming  magnesian  lime- 
stone, or  dolomite.  Exists  in  the  waters  of  the  ocean,  as 
a  chloride,  and  of  many  mineral  springs,  as  a  sulphate. 
Enters  into  the  composition  of  many  rocks  and  minerals. 
Properties.  —  Resembles  silver  in  color  and  lustre,  zinc 
in  fusibility  and  volatility.  Yery  ductile,  and  malleable; 
crystallizes  in  octahedrons.  Not  acted  upon  by  cold, 

oxidized  by  hot  water. 
Burns  in  air  producing 
a  brilliant  white  light, 
capable  of  employ- 
ment for  illuminating 
and  photographic  pur- 
poses. Sp.  Gr.  l.Y. 

In  order  to  make  its 
combustion  regular  in 
these  cases,  the  mag- 
nesium, in  the  form  of 
a  narrow  ribbon,  is 
fed  by  clockwork,  from 


147. 


MAGNESIUM.  197 

a  brass  nozzle,  A,  beyond  which  it  burns.  This  appara- 
tus, known  as  a  Magnesium  Lamp,  is  shown  in  Fig.  147. 
The  clock-work  is  contained  in  B  C,  its  motion  is  con- 
trolled by  the  fly-wheel,  B,  and  it  is  wound  up  by  the  key, 
I).  The  mirror,  E  F,  reflects,  and  concentrates  the  light, 
and  the  whole  apparatus  may  rest  on  a  table,  or  be  held 
by  the  handle,  Gr.  This  light  has  been  used  to  photograph 
dark  interiors,  coal-mines,  the  pyramids,  etc.,  and  to  take 
photographic  portraits,  at  night.  Though  very  brilliant, 
its  luminosity  does  not  approach  that  of  the  lime,  or 
electric  light,  except  in  respect  of  V  actinic"  rays,  in  which 
it  is  the  most  powerful  of  all. 

Oxide  of  Magnesium — MgO.  Magnesia;  Calcined  Mag- 
nesia. Prepared  by  driving  off  the  carbonic  acid  and 
water  contained  in  magnesia  alba  by  long  continued 
heat ;  a  soft,  bulky,  white,  tasteless,  and  nearly  insoluble 
powder. 

Carbonate  of  Magnesia— MgO, C02.  Occurs  in  nature, 
in  rhombohedral  crystals — magnesite.  Mixed  with  hydrate 
of  magnesia,  it  forms  the  subcarbonate  of  magnesia,  or 
magnesia  alba  of  pharmacy,  4(MgO,C02  -f  MgO, HO  -f- 
6HO.) 

Sulphate  of  Magnesia— MgO, S03-f  6HO.  Epsom  Salts. 
Formed  by  dissolving  magnesian  limestone  in  sulphuric 
acid,  and  separating  the  sparingly  soluble  sulphate  of 
lime  by  filtration  ;  thus,  MgO,C02  -f  CaO,CO2  + 
2(HO,SO3)  =  MgO,S03  +  CaO,S03  -f  2HO  +  2C02. 
Extensively  used  as  a  purgative. 

Phosphate  of  Magnesia  and  Ammonia— 2MgO,NH40,PO5 
-f  12HO.  When  it  is  desired  to  remove  magnesia  from 
solution,  it  may  be  done  by  adding  some  soluble  phos- 
phate, together  with  ammonia ;  when  an  insoluble  phos- 
phate of  magnesia  and  ammonia  is  formed. 

Silicates  of  Magnesia.  —  Occur  native  as  Talc,  2(MgO, 
SiO3)  + 2MgO,3Si03;  Steatite  or  Soapstone,  MgO,SiO3 


198  ALUMINUM. 

4-2MgO,3Si03;  Meerschaum,  2MgO,3Si03  +  4Aq ;  Ser- 
pentine, 2(MgO,Si03)  +  MgO-f  2Aq. 

Character  of  the  Magnesian  Salts. — Bitter  to  the  taste. 
Many  magnesian  minerals  have  a  silky  lustre,  and  feel 
unctuous  to  the  touch. 

Test.  — A  white  precipitate,  with  the  alkalies  and  their 
carbonates. 

GROUP  III. 

Metals  of  the  Earths. 

Sym.  Al.  ALUMINUM.  Eq.  13.7. 

First  procured  by  Wohler,  in  1827,  by  decomposing 
Chloride  of  Aluminum  in  a  platinum  tube,  by  means  of 
Potassium,  A1.2C13  +  3  K  =  3  KC1  -f  2  Al. 

Properties.  —  In  color  and  hardness,  aluminum  closely 
resembles  zinc.  It  may  be  rolled  into  very  thin  foil,  and 
drawn  out  into  fine  wire.  It  conducts  electricity  almost 
with  the  rapidity  of  silver ;  struck  with  a  hard  body,  it 
gives  a  clear  and  musical  ring.  On  account  of  its  light- 
ness—  being  but  2^  times  heavier  than  water  —  and  its 
inalterability  in  air,  many  attempts  have  been  made  to 
employ  aluminum  as  a  substitute  for  silver,  in  articles  of 
jewelry,  and  table  use.  Sp.  Gr.  2.5. 

Sesquioxide  of  Aluminum,  or  Alumina— A 1203.  When 
this  earth  is  found  crystallized  in  nature,  and  of  a  dark 
red  color,  it  is  known  as  oriental  ruby ;  when  blue,  as 
sapphire;  green,  oriental  emerald;  if  it  is  yellow,  it  is 
called  oriental  topaz;  and  if  violet,  oriental  amethyst. 
To  the  dark-colored  and  dingy  crystals  the  name  of 
corundum  is  given,  and  to  the  granular  masses,  so 
valuable  for  polishing,  the  term  emery  is  applied. 

It  is  obtained  as  a  gelatinous  hydrate,  when  carbo- 
nate of  ammonia  is  added  to  the  sulphate,  or  other 
salt  of  alumina :  A12O3,3  SO3  +  3  (NH4O,C02)  +  Aq  = 


ALUMINUM.  199 

3HO,A12O,  +  3(NH40,S03)  -f  3C02  -f  Aq.  In  this  con- 
dition it  dissolves  readily  in  potash  and  acids,  but  if 
rendered  anhydrous  by  ignition,  it  dissolves  with  diffi- 
culty. 

Uses. — Alumina  has  a  strong  attraction  for  water,  of 
which  it  retains  no  less  than  15  per  cent. ;  hence,  the 
value  of  clay  as  an  ingredient  of  the  soil. 

It  forms  with  most  coloring-matters,  insoluble  com- 
pounds, called  lakes.  If  the  dyer  were  to  soak  his  cali- 
coes in  the  dyestuff  alone,  the  color  would  be  removed 
from  the  cloth  at  the  first  washing.  He  first  immerses 
them  in  a  solution  of  some  mordant  like  alumina,  which 
has  an  attraction  for  both  the  cotton  fibre  and  the  color- 
ing material,  strong  enough  to  resist  the  action  of  water. 
To  obtain  the  alumina  for  this  purpose,  alum  (KO,S03  -f- 
A1203,3S03  -f  24HO),  which  has  been  manufactured  by 
the  process  described  under  Chloride  of  Potassium,  page 
182,  is  decomposed  by  carbonate  of  soda ;  the  cotton 
fibre  forms  a  strong  mechanical  combination  with  the 
alumina  thus  set  free,  by  which  it  is  enabled  to  hold  the 
coloring-matter  fast. 

Besides  its  above-mentioned  use,  alum  is  employed  in 
the  sizing  of  paper,  the  preparation  of  sheep-skins,  and  in 
clarifying  sugars,  etc. 

Silicates  of  Alumina.  —  When  silicate  of  alumina 
(A1203,3S03)  is  combined  with  silicate  of  lime  (CaO, 
Si03),  it  produces  a  number  of  minerals,  which  have  the 
remarkable  property  of  boiling  up,  on  being  heated  in  the 
blowpipe  flame,  and  are  therefore  called  zeolites,  from 
£*'«•,  /  boil.  Combined  with  the  silicates  of  potassa,  soda, 
lithia,  or  lime,  silicate  of  alumina  forms  feldspar,-  and 
feldspar,  when  mingled  with  quartz  and  mica,  produces 
the  well-known  gneiss  and  granite  rocks.  The  beautiful 
topaz  is  a  silicate  of  alumina  combined  with  fluoride  of 
aluminum, '  A12PS;  and  the  Bohemian  garnet,  so  highly 


200  GLASS. 

prized  for  its  intense  blood-red  color,  is  a  silicate  of  alu- 
mina colored  by  the  sesquioxides  of  iron  and  chromium. 

Uses. — When  the  granite  rocks  crumble  away  beneath 
the  slow  but  resistless  action  of  storms  and  rain,  they 
afford  the  different  varieties  of  clay.  The  latter,  when 
stained  by  sesquioxide  of  iron,  is  used  as  a  pigment  under 
the  name  of  yellow  and  red  ochre  ;  if  free  from  stains  of 
iron  it  is  called  pipe-clay,  and  is  largely  manufactured  into 
tobacco  pipes.  A  peculiar  variety  of  clay  is  termed  kaolin. 
It  is  of  the  highest  importance,  because  it  forms,  by 
fusion  with  silicate  of  potassa  and  lime,  porcelain  and 
China.  When  the  clay  and  other  ingredients  used  in 
pottery  are  not  so  pure  and  fine,  the  various  kinds  of 
stoneware  and  earthenware  are  formed.  A  porous  clay, 
which  has  the  property  of  drinking  oil  and  grease  into 
its  capillary  vessels,  is  extensively  used  for  scouring 
woollens  and  cloths,  under  the  name  of  fuller's  earth. 


GLASS. 

When  silica,  obtained  from  quartz  rock  or  pure  white 
sand,  is  fused  with  the  carbonates  of  potash  and  lime,  a 
double  silicate  of  potash  and  soda  is  formed,  which  is 
known  under  the  name  of  Bohemian  and  crown-glass. 
The  former  can  be  submitted  to  intense  heat  without 
melting,  and  is  therefore  invaluable  to  the  chemist  in  the 
combustion  of  organic  bodies.  The  latter  is  combined 
with  flint-glass  to  correct  the  chromatic  aberration  of 
lenses. 

If  soda  is  used  instead  of  potash,  a  double  silicate  of 
soda  and  lime  is  formed ;  and  this  is  familiar  to  us  as 
French  plate,  and  ordinary  window-glass.  The  above 
silicates  are  mixed  with  clay  and  oxide  of  iron,  when  it 
is  unnecessary  to  preserve  the  transparency  of  the  glass ; 
and  in  this  manner  wine-bottles,  carboys,  etc.,  are  made. 


GLUCTNUM,    ETC.  201 

Character  of  Alumina  Salts. — They  all  have  an  alum- 
like  taste  ;  turn  blue  litmus-paper  red ;  give  an  azure  with 
nitrate  of  cobalt  before  the  blowpipe,  and  a  bulky  gelatinous 
precipitate  with  ammonia. 


Sym.  Gl.  GLUCINUM.  Eq.  26.5 

Discovered  by  Wohler.  It  derives  its  name  from  y*.vxv$, 
sweet,  in  allusion  to  the  remarkable  taste  of  its  salts. 
When  combined  with  silica  and  alumina  it  forms  the 
beautiful  green  beryl  and  emerald. 


Sym.  Zr.  ZIRCONIUM.  Eq.  24.6. 

Isolated  by  Berzelius.  It  occurs  in  nature  as  a  silicate, 
forming  zircon  and  the  bright  red  hyacinth. 

THORIUM  (Th,  59.6),  YTTRIUM  (Y,  32.2),  ERBIUM 
(Er,  — ),  TERBIUM  (Tb,  — ). 

Thorium  is  remarkable  as  occurring  in  the  form  of  a 
protoxide,  ThO,  forming  the  earth,  thoria.  It  was  dis- 
covered by  Berzelius,  in  1829.  in  a  rare,  black  mineral 
named  thorite,  which  is  found  in  Norway. 

Yttrium  was  found  by  Wohler,  and  Erbium  and  Terbium 
by  Mosander,  1843,  in  a  mineral  called  gadolinite,  which 
occurs  at  Ytterby,  in  Sweden. 


CERIUM  (Ce,  47.),  LANTHANUM  (Ln,  47),  DIDY- 

MIUM  (Dy,  48). 

The  first  of  these  rare  metals  was  discovered  by  Klap- 
roth,  and  the  other  two  by  Mosander,  1839,  in  Gerite. 
They  are  so  little  known  that,  until  recently,  they  were 
all  confounded  together,  under  the  name  of  Cerium. 


202  MANGANESE. 

Metals  Lately  Discovered  by  means  of  the  Spectral 
Analysis. 

Sym.  Rb.  RUBIDIUM.  Eq.  85. 

Bunsen  and  Kircboff,  1860.  Both  Rubidium  and 
Ceesium  were  originally  found  in  the  mother  liquor  of 
mineral  waters ;  particularly  of  the  salt-springs  at  Durk- 
heimer.  They  have  since  been  met  with  in  a  few  minerals, 
as  lepidolite.  Rubidium  produces  in  the  spectroscope 
two  bright  red  lines  beyond  Frauenhoffer's  line  A ;  and 
hence  in  a  part  of  the  spectrum  usually  invisible.  (See 
plate  facing  page  123.  Rb). 

Sym.  Cs.  CAESIUM.  Eq.  133.03. 

Bunsen.  Distinguished  by  two  blue  lines  in  the  spec- 
trum ;  which  are  of  great  intensity  and  sharpness  of  out- 
line. (See  plate  facing  page  123.  Ce). 


Sym.Tl.  THALIUM.  Eq.  204. 

Crookes.  Found  in  Lipari  sulphur  and  pyritous  ores. 
Gives  a  green  lime  in  spectrum.  (See  plate,  Tl.) 

Sym.  In.  INDIUM.  Eq.  37.07, 

According  to  Reich  and  Richter;  but  35.918  as  given 
by  a  later  authority.  Found  in  Freiburg  ores  of  arsenical 
pyrites,  blende,  and  galena.  Gives  dark  blue  lines. 

GROUP  IV. 

Metals  whose  Oxides  form  strong  Bases. 
Sym.  Mn.  MANGANESE.  Eq.  27.67. 

Discovered  by  Gahn,  in  11t4.  Found  principally  in 
the  state  of  black  oxide,  Mn02,  as  Pyrolusite. 

Preparation. — An  artificial  oxide  is  obtained  by  calcining 


MANGANESE.  203 

the  carbonate  in  a  well  closed  vessel.  This  is  mixed  with 
oil  and  ignited  in  a  covered  crucible,  by  which  means  the 
oil  is  converted  into  charcoal  very  intimately  mixed  with 
the  oxide.  The  above  process  is  repeated  several  times. 
The  mixture  is  next  made  into  a  thick  paste  with  oil  and 
introduced  into  a  crucible  lined  with  charcoal,  and  filled 
in  with  charcoal-dust.  This  is  then  heated  to  redness, 
after  which  the  cover  is  well  luted  down  and  the  whole 
exposed  for  an  hour  and  a  half  to  the  greatest  heat  of  a 
wind  furnace.  The  metal  is  found  as  a  button  at  the 
bottom  of  the  crucible. 

Properties. —  Manganese  is  a  greyish  white  metal  like 
cast-iron ;  oxidizes  rapidly  in  the  air ;  in  water  it  evolves 
hydrogen.  Sp.  Gr.  8.013,  7.05,  6.850,  and  t.Q,  according 
to  different  authorities. 

Compounds  with  Oxygen. 

Protoxide— MnO. 

Forms  the  basis  of  the  common  salts  of  Mn.  They 
are  similar  in  form,  or  isomorphous,  with  those  of  mag- 
nesia and  protoxide  of  zinc.  They  are  neutral,  and  of  a 
pale  rose  color. 

Sesquioxide— Mn203. 

Sources. — Braunite  ;  and,  as  a  hydrate,  manganite. 

Properties. — A  feeble  base,  isomorphous  with  alumina 
and  sesquioxide  of  iron. 

Use.  —  All  the  materials  employed  in  the  manufacture 
of  glass  contain  a  small  quantity  of  iron,  \vbich  stains  the 
glass  yellow-green.  To  remove  this  stain,  black  oxide  of 
manganese  or  glass-maker's  soap  is  cautiously  added.  The 
black  oxide  becomes  converted  into  the  sesquioxide  of 
manganese;  and  the  violet  tinge  communicated  by  the 
latter  to  glass,  exactly  counteracts  the  yellow  color  due 
to  the  presence  of  iron.  This  same  oxide  imparts  its 
beautiful  violet  tint  to  amethyst. 


204  MANGANESE. 

Binoxide — MnO2. 

Sources. — Pyrolusite,  psilomelane. 

Use. —  Mixed  with  acids,  affords  an  excellent  oxidizing 
agent ;  ignited,  gives  off  one-third  of  its  oxygen,  leaving 
the  red  oxide :— 3Mn02=(MnO,Mn803)-f20 ;  heated  with 
concentrated  sulphuric  acid,  it  yields  half  its  oxygen : — • 
Mn02  +  HO,S03  =  MnO,S03  +  HO  +  0  ;  extensively 
employed  in  manufacturing  chlorine: — Mn02+2HCl=Mn 
Cl  +  2HO  +  Cl.  It  is  largely  used  in  making  bleaching 
powder,  18,000  tons  being  annually  consumed  in  England 
for  this  purpose  alone. 

Permanganic  Acid— Mn207. 

When  manganate  of  potassa  or  chameleon  mineral, 
KO,Mn08,  .formed  by  heating  equal  weights  of  caustic 
potash  and  binoxide  of  manganese,  is  thrown  into  water, 
it  first  becomes  green,  then  purple,  and  at  last  claret- 
colored  ;  and  a  permanganate  of  potash,  KO,Mn207,  is 
formed. 

Use.  —  As  an  oxidizing  agent.  If  permanganate  of 
potash  be  added  to  sulphuric  or  hydrochloric  acid  contain- 
ing sulphurous  acid  in  solution,  the  sulphurous  acid  is 
oxidized  to  sulphuric  by  the  permanganate  of  potash, 
while  the  latter  at  the  same  time  loses  its  color ;  it  may 
therefore  be  employed  to  detect  the  sulphurous  acid. 

Sulphate  of  Manganese— MnO,S03+mo. 

Preparation. —  Formed  by  heating  the  binoxide  in  sul- 
phuric acid. 

Use. — When  cloths  moistened  with  this  salt  are  passed 
through  a  solution  of  bleaching-powder,  an  insoluble  hydrate 
of  the  binoxide  is  thrown  down  upon  the  woollen  or  cotton 
fibre,  and  dyes  it  a  permanent  brown. 

Character  of  the  Salts  of  Manganese.  —  They  have  a 
pale  rose  color  and  an  astringent  taste.  Before  the  blow- 
pipe they  give,  with  borax,  an  amethystine  bead  in  outer 
flame ;  with  carbonate  of  soda,  a  bluish-green  bead ;  with 


IRON. 


205 


hydrosulpJiate   of  ammonia,  a   flesh-colored   precipitate ; 
with  the  alkalies  and  their  carbonates,  give  a  white. 


Sym.  Fe, 


IRON. 


Eq.  28, 


Sources. — Pure  in  stones  of  meteoric  origin  ;  as  an  ore, 
everywhere  abounds. 

Properties. — White  color,  perfect  lustre,  highly  mallea- 
ble, ductile  ;  most  tenacious  of  all  metals  ;  oxidizes  in  dry 
air,  and  decomposes  water  at  a  red  heat ;  strongly  mag- 
netic. Sp.  Gr.  7.8. 

Protoxide— FeO.  Fig.  us. 

Preparation.  —  Precipitates  as  a 
white,  bulky  hydrate,  when  an  al- 
kali is  added  to  any  protosalt  of 
iron. 

Properties.  —  Absorbs  oxygen  ra- 
pidly, and  changes  to  sesquioxide. 
It  is  a  powerful  base,  and  forms  salts 
isomorphous  with  magnesia  and  ox- 
ide of  zinc ;  which  have  a  pale  green 
color  and  an  astringent  taste. 

Sesquioxide — Fe203. 

Sources. — Anhydrous,  the  specu- 
lar iron  ore    and  red  hcematite  ;   as   a   hydrate,   brown 
hcematite. 

Properties. — Forms  with  acids,  reddish  salts  of  an  acid 
reaction  and  astringent  taste  ;  with  the  more  powerful 
bases  it  displays  the  part  of  an  acid.  Combines,  for 
example,  with  protoxide  of  iron  to  form  black  oxide,  Fe3 
04=  FeO,Fe.203.  The  black  oxide  also  exists  in  nature 
as  the  loadstone,  forming  a  valuable  ore  of  iron,  and  a 
source  of  magnetism.  Fig.  148. 
18 


206  IRON. 

Ferric  Acid— Fe03. 

Preparation.  —  By  oxidizing  sesquioxide  of  iron  with 
nitre,  at  a  red  heat. 

Properties. — Forms  salts  easily  decomposed  by  organic 
matter ;  and,  with  the  exception  of  Ferrate  of  Baryta, 
very  unstable. 

With  chlorine,  iodine,  and  bromine,  iron  forms  proto 
and  sesquisalts. 

Sulphides  of  Iron. 

ProtosulpMde— Fe  S. 

Preparation.  —  Four  parts  of  powdered  sulphur  are 
strongly  heated  with  7  parts  of  iron  filings. 

Uses. — It  is  a  black,  brittle  substance  employed  in  the 
laboratory  as  a  source  of  sulphuretted  hydrogen.  FeS  -f- 
HO,S03=FeO,S03+HS.  When  60  parts  of  iron  filings, 
2  of  sal  ammoniac,  and  1  of  sulphur,  all  in  powder,  are 
made  into  a  paste  with  water  and  applied  immediately  as 
a  luting  to  iron  vessels,  it  quickly  sets  as  hard  as  iron 
itself,  by  the  formation  of  a  sulphide. 

Bisulphide— FeS2. 

Sources.  —  Exists  as  iron  pyrites  or  fool's  gold ;  and 
appears  in  many  cases  to  be  derived  from  the  deoxidation 
of  sulphate  of  iron  by  organic  matter.  Combined  with 
the  protosulphide,  forms  magnetic  pyrites  (2FeS,FeS.2), 
and  with  arsenic,  arsenical  pyrites  or  mispickel  (FeS2)Fe 
As). 

Use.  —  Under  the  name  of  mundic,  iron  pyrites  is 
largely  employed  in  the  manufacture  of  sulphuric  acid  to 
afford  sulphurous  acid  by  ignition  in  the  open  air.  Mis- 
pickel is  roasted  to  form  arsenious  acid,  As03 — the  white 
arsenic  of  the  shops. 

Carbides  of  Iron. 

WMte 'Cast-Iron  is  a  compound  of  4  equivalents  of  iron 
with  1  of  carbon,  Fe4C.  Malleable  iron  is  cast-iron  from 


CARBIDES   OF   IRON. 


20T 


which  nearly  all  the  silicon  and  more  than  four  per  cent, 
of  carbon  has  been  burnt  out  by  being — 1st.  Heated  in 
contact  with  air — refining.  2nd.  Heated  with  black  oxide 
of  iron — puddling.  In  this  way  but  one-half  per  cent,  of 
carbon  is  left  in  the  purest  bar-iron.  Steel  is  malleable 
iron  which  has  been  heated  to  redness  with  charcoal  for 
about  48  hours — cementation.  It  contains  from  1.8  to  2.3 
per  cent,  of  carbon. 

By  Bessemer's  process,  malleable  iron  and  steel  are 
made  from  pig-iron  without  the  aid  of  fuel,  by  causing 
hot  air  to  pass  through  the  liquid  iron.  The  carbon  is 
burnt  away  with  the  formation  of  carbonic  oxide,  and 
develops  in  its  combustion  sufficient  heat  to  continue  the 
operation  without  the  assistance  of  external  fire. 

This  process  is  conducted  in  a  large  iron  vessel  (Fig.  149) 

Fig.  149. 


called  a  "  converter,"  capable  in  some  cases  of  containing 
five  tons  of  iron.  Air  is  carried  from  condensing  p'umps 
into  this  vessel  through  the  trunion  A,  whence  it  passes 
by  a  pipe,  B,  to  the  bottom,  and  so  escapes  into  the  melted 
iron  within. 

When   the   operation   is  finished,  the  molten  steel  is 


208  COMPOUNDS    OF    PROTOXIDE    OP    IRON. 

poured  out  (by  turning  the  converter  over  with  appropriate 
machinery)  and  run  into  moulds.  The  quality  of  this 
steel  is  much  improved  by  mixing  with  it,  after  conversion, 
a  small  amount  of  iron  containing  manganese. 

In  smelting,  sulphides,  nitrides,  and  phosphides  of  iron 
are  formed  in  small  quantities.  They  all  have  deleterious 
effects  ;  rendering  bar-iron  brittle  or  cold  short. 

Compounds  of  Protoxide  of  Iron. 

Sulphate  of  Protoxide  of  Iron— FeO,S03+7Aq.  Cop- 
peras, Green  Vitriol. 

Preparation.  —  Obtained  by  dissolving  iron  in  dilute 
sulphuric  acid,  or  by  roasting  iron  pyrites. 

Properties. — Forms  large  green  crystals,  which  slowly 
effloresce  and  absorb  oxygen  in  the  open  air;  forming  a 
subsulphate  of  the  sesquioxide.  Combines  with  the  sul- 
phates of  potassa  and  soda  to  form  double  sulphates 
isomorphous  with  those  formed  by  the  alkaline  sulphates 
with  sulphate  of  copper.  (FeO,S03-f  KO,S03+6Aq)  and 
(CuO,SO8+NaO,S03+6Aq). 

Uses. — As  a  reducing  agent.  It  is,  therefore,  employed 
to  precipitate  gold  and  palladium  from  solution  in  the 
metallic  state ;  and  to  develop  photographs,  by  removing 
all  the  oxygen  from  the  silver  salt ;  thus,  3  (AgO,N05)  -f 
6(FeO,S03)  =  2(Fe203,3S03)  -f  Fe203,3N05  f  Aq.  To 
form  Nordhausen  sulphuric  acid,  2(FeO,SO3-f  1Aq)= 
Fe203  +  S02  -f  13  Aq  +  HO,S03.  The  sesquioxide  of 
iron  produced,  as  it  will  be  noticed,  in  this  reaction,  is 
sold  as  a  polishing  powder  for  glass  and  jewellers'  ware, 
and  as  a  red  pigment,  under  the  names  of  colcothar, 
crocus  of  Mars,  and  rouge. 

Persulphate,  or  Sesquisulphate— Fe^03,3S03. 

Source.  —  Native  in  Chili,  forming  a  white  powder 
having  the  composition  Fe203,3S03  -f  9Aq. 

Properties.  —  Forms  double  salts  with  the  alkalies,  re- 


COBALT.  209 

sembling  common  alum  in  form,  composition,  and  taste. 
E.  g.  NH,0,S03  +  Fe A,  3  SOB  +  24  Aq. 

Note.  —  Salts  of  a  metallic  protoxide  are  frequently 
termed  -ous  salts,  of  a  higher  oxide  -ic  salts. 

A  ferrous  and  a  ferric  nitrate  (FeO,N05  +  6  Aq),  and 
(Fe203,3N05)  may  be  formed,  as  well  as  a  ferrous  ace- 
tate, and  a  ferric  oxalate ;  but  they  are  not  important. 

Carbonate  of  Protoxide  of  Iron— FeO,C02. 

Sources. — The  two  valuable  ores,  spathic  iron  and  clay, 
iron-stone,  and  ferruginous  springs.  The  excess  of  car- 
bonic acid  in  chalybeate  springs  holds  the  carbonate  of 
iron  in  solution,  and  when  the  carbonic  acid  escapes, 
oxygen  is  absorbed  from  the  air,  and  ochry  hydrated 
sesquioxide  of  iron  produced. 

Tests.  —  Ferrous  salts,  with  ferrocyanide  of  potassium, 
precipitate  TurnbulPs  blue. 

Ferric  salts,  with  ferrocyanide  of  potassium,  precipitate 
Prussian  blue :  this  freshly  prepared  dissolves  in  a  solu- 
tion of  oxalic  acid,  giving  blue  writing  fluid.  With  sul- 
phocyanide  of  potassium  give  a  blood-red  precipitate; 
with  tincture  of  nut-galls  forms  ink.  (See  page  251.) 


Sym.  Co.  COBALT.  Eq.  29.5. 

Discovered  by  Brandt,  in  It 33. 

Sources.  —  Tin- white  cobalt,  Co,  As,  and  cobalt  glance, 
CoS2,CoAs. 

Properties. — Reddish-gray  color  ;  hard  ;  brittle  ;  almost 
as  magnetic  and  infusible  as  iron.  Slowly  oxidizes  in  air. 
Not  used  in  the  metallic  state,  but  in  combination  forms 
beautiful  pigments.  Sp.  Gr.  8.5. 

It  has  three  oxides ;  the  protoxide,  CoO ;  sesquioxide, 
Co203;  and  cobaltic  acid,  Co3O5. 

Uses. — Zaffre,  used  in  enamel-painting,  is  an  impure 
oxide  of  cobalt  (made  by  roasting  cobalt  ore),  mixed  with 
18* 


210  NICKEL. 

2  or  3  times  its  weight  of  sand.  Smalt  is  a  glass  colored 
blue  by  oxide  of  cobalt.  With  alumina,  oxide  of  cobalt 
forms  cobalt-ultramarine,  or  Thenard's  blue  ;  with  oxide 
of  zinc,  Einman's  green. 

Chloride  of  Cobalt—  CoCl. 

Preparation.  —  Formed  by  dissolving  the  oxide  in  hy- 
drochloric acid,  CoO  +  HC1  =  CoCl,HO. 

Uses. — When  writing  is  executed  in  dilute  chloride  of 
cobalt,  the  rose-red  marks  made  by  the  hydrated  chloride 
are  so  faint  as  to  be  invisible,  but  when  the  water  is 
driven  off  by  heating  the  paper,  distinct  lines  are  visible 
of  anhydrous  chloride  of  cobalt,  and  of  the  blue-color 
characteristic  of  this  salt  in  its  anhydrous  state  —  sympa- 
thetic ink. 

Tests. — With  the  alkalies,  a  blue  precipitate ;  with  their 
carbonates,  a  pink. 


Sym.  Ni.  NICKEL.  Eq.  29.6. 

First  recognized  as  a  distinct  metal  by  Cronstedt,  in 
1751. 

Sources. — Associated  with  cobalt,  to  which  it  bears  a 
close  likeness,  in  meteorites,  and  various  ores  ;  extracted 
from  kupfernickel,  Ni2As,  and  arsenical  nickel,  NiAs. 

Properties. — A  white,  hard,  malleable,  ductile,  very 
tenacious,  difficultly  fusible  metal.  Strongly  magnetic 
at  temperatures  below  630°.  Oxidized  by  air  at  high 
temperatures.  Most  nickelliferous  compounds  have  a 
green  color.  An  alloy  of  51  parts  of  copper,  30.6  of 
zinc,  and  18.4  of  nickel,  is  highly  prized  for  its  mallea- 
bility and  silvery  lustre,  and  is  well  known  under  the 
name  of  German  silver.  Sp.  Gr.  8.8. 

The  Oxides  of  Nickel,  NiO,  and  Ni203;  its  sulphides, 
NiS,Ni2S,  and  NiS2;  chloride,  NiCl;  sulphate  (NiO,SO3 
+  7  Aq),  which  forms  with  potassa  and  ammonia  beauti- 


CHROMIUM.  211 

fill  double  salts  (NiO,S03  +  KO,SOa  -f  6  HO)  and 
(NiO,S03  +  NH40,S03  +  6  HO)  ;  and  the  various  basic 
carbonates  of  nickel  have  at  present  no  industrial  ap- 
plication. 


Sym.  Cr.  CHROMIUM.  Eq.  26.7. 

Discovered  by  Vauquelin,  in  Vauquelinite,  chromate 
of  lead,  in  the  year  1791. 

Sources. — Chrome  iron,  FeO,Cr203. 

Properties.  —  A  dark-grey  metal,  possessing  a  strong 
affinity  for  oxygen  ;  oxidizes  in  the  open  air  below  red 
heat,  and  deoxidizes  nitric  acid  with  violence.  Sp.  Gr. 
6.81. 

Uses. — Not  employed  in  the  metallic  state,  but  as  an 
oxide  and  chromate  largely  used  in  painting  on  porcelain, 
and  in  calico  printing. 

Compounds  with  Oxygen. 

These  are  5  in  number,  and  agree  in  composition  and 
properties  with  the  corresponding  ferric  compounds  ;  the 
protoxide,  CrO,  is  a  powerful  base,  forming  pale-blue 
salts ;  the  sesquioxide,  Cr203 ,  is  a  feeble  base,  and  forms 
poisonous  green  salts.  It  is  not  decomposed  by  heat,  and 
is,  therefore,  used  to  color  enamel  green.  CrO,Cr203  cor- 
responds to  Magnetic  Oxide  of  Iron ;  Cr03,  Chromic  Acid, 
to  Manganic  and  Ferric  acids;  Cr207,  to  Permanganic  acid. 

Chromic  Acid  —  Cr03. 

Preparation.  — 100  measures  of  saturated  solution  of 
bichromate  of  potassa  are  mixed  with  150  measures  of 
sulphuric  acid,  KO,2Cr03  +  HO,S03  =  KO,S03  +  HO 
-f  2Cr03. 

Properties.  —  As  thus  made,  chromic  acid  forms  bright 
red  crystals,  which  are  very  deliquescent,  and  easily 


212  ZINC. 

decomposed  into  sesquioxide  of  chromium,  by  contact 
with  organic  matter.  Hence  its  use  as  an  oxidizing 
agent.  It  forms  three  classes  of  salts — basic,  neutral,  and 
acid.  Of  these  the  bichromate  of  potassa,  KO,2Cr03, 
is  most  important ;  it  is  used  in  dyeing,  in  the  formation 
of  aniline  colors,  and  in  photography.  With  logwood  it 
makes  a  good  ink ;  3  oz.  of  solid  extract  of  logwood  are 
dissolved  in  3  gallons  of  hot  water;  to  this  is  added  -J  oz. 
of  KO,2O03,  dissolved  also  in  a  little  hot  water.  The 
ink  is  then  ready  for  use.  The  chromate  of  lead,  PbO, 
Cr03,  is  the  well-known  chrome-yellow.  Subchromate  of 
lead,  2PbO,Cr03,  which  is  formed  by  dipping  the  cloth 
moistened  with  chromate  of  lead  into  boiling  milk  of  lime, 
2(PbO,Cr03)  +  CaO,HO  =  2PbO,Cr03+CaO,Cr03  +  HO, 
is  largely  employed  in  dyeing. 

Tests. — With  salts  of  lead,  the  chromates  give  a  yellow 
precipitate ;  with  nitrate  of  silver,  a  red  ;  with  subnitrate 
of  mercury,  an  orange. 

Compounds  with  Chlorine. 

Protochloride,  CrCl,  valuable  as  a  reducing  agent, 
owing  to  its  intense  affinity  for  oxygen,  and  the  Sesqui- 
chloride,  Cr2Cl3. 

Sym.  Zn.  ZINC.  Eq.  32.6. 

Known  in  commerce  since  the  time  of  Paracelsus,  1540. 

Source.  —  The  chief  ores  of  Zinc,  or,  as  it  is  called  in 
commerce,  Spelter,  are  the  Red  Oxide,  ZnO,  found  at 
Franklin,  New  Jersey;  Blende,  ZnS,  found  in  Cornwall 
and  Cumberland,  England,  in  Saxony,  and  throughout 
Missouri,  Wisconsin,  Iowa,  etc. ;  Smithsonite,  ZnO,C02, 
worked  in  Silesia,  Belgium,  and  England;  Calamine, 
a  hydrated  Silicate  of  Zinc,  found  in  Carinthia  and  near 
Bethlehem,  Pennsylvania. 


ZINC.  213 

Extraction  from  Ores. — First  powdered,  then  roasted, 
to  drive  off  sulphur  or  carbonic  acid,  ZnS-f-30=ZnO-f 
SO2;  ZnO,C02=ZnO  +  C02;  and  afterwards  mixed  with 
coke  and  distilled,  ZnO-f  C=Zn+CO. 

Properties. — Hard,  bluish-white  metal ;  brittle  at  ordi- 
nary temperatures,  malleable  and  ductile  between  200° 
and  300°,  very  brittle  at  higher  temperatures;  fuses  at 
173° ;  boils  at  1904°,  its  vapor  burning  brilliantly  on  ex- 
posure to  air.  In  a  moist  atmosphere  Zinc  is  soon  coated 
with  oxide,  which  prevents  a  deeper  oxidation  and  fits  it 
for  many  industrial  uses.  Moistened  with  water  Zinc 
combines  at  ordinary  temperatures  with  chlorine,  bro- 
mine, and  iodine.  Sp.  Or.  6.8  to  Y.I. 

Uses. — Metallic  zinc  is  used  for  roofing,  and  as  the  oxida- 
ble  metal  in  galvanic  batteries.  When  sheet-iron  is  plunged 
into  moulten  zinc  and  sal  ammoniac  the  Oxide  of  Zinc  is 
dissolved  by  the  sal  ammoniac  as  fast  as  formed,  and  the 
two  metals  are  firmly  united,  forming  galvanized  iron. 
Brass  is  an  alloy  of  2  parts  of  copper  and  1  of  zinc.  The 
Oxide  of  Zinc,  ZnO,  is  sometimes  substituted  for  white 
lead,  under  the  name  of  Zinc  White,  but  is  not  so  opaque 
and  dead-white ;  it  is  substituted  for  red  lead  in  optical 
glass ;  in  an  impure  state,  as  obtained  from  the  flues  of 
furnaces  in  which  brass  is  melted,  it  is  sold  as  putty. 
Pure  ZnO  is  prepared,  as  at  Bethlehem,  Pennsylvania, 
by  roasting  Zinc  ores  (such  as  the  Silicate)  in  open  fires 
and  carefully  collecting  the  white  fumes  passing  off. 
Chloride  of  Zinc,  ZnCl,  when  in  solution,  is  employed  as 
an  antiseptic  and  as  a  preservative  of  wood.  The  double 
Chloride  of  Zinc  and  Ammonium  (NH4Cl-f  ZnCl)  is  em- 
ployed to  remove  the  ozide  from  Zinc,  in  the  process  of 
soldering. 

Sulphate  of  Zinc— ZnO,S03-f-YAq.  White  Vitriol  is  a 
powerful  emetic ;  employed  largely  in  calico  printing. 

Tests. — White  precipitates  with  all  the  usual  reagents. 


214  CADMIUM— COPPER. 


Sym.  Cd.  CADMIUM.  Eq.  56. 

Discovered  by  Stromcyer,  181 T. 

Sources. — Accompanies  the  ores  of  zinc ;  Greenockite, 
CdS. 

Properties. — Has  a  color  and  cry  resembling  tin  ;  very 
soft,  malleable  and  ductile;  fuses  at  442°;  boils  at  1580°; 
burns  with  salmon-colored  fumes.  Sp.  Gr.  8.6. 

Uses. — Forms  very  fusible  alloys ;  thus,  4  parts  of  Pb,  7 
parts  of  Bi,  1.5  parts  of  Cd,  and  2  parts  of  Sn  form  an 
alloy,  fusing  at  140°  Fahr.  Sulphide  of  Cadmium,  CdS, 
forms  an  excellent  bright-yellow  pigment ;  the  Iodide,  Cdl, 
is  employed  by  photographers  to  iodize  collodion. 

Test. — Yellow  precipitate  of  Sulphide  with  Sulphuretted 
Hydrogen  and  Sulphide  of  Ammonium. 


Sym.  Co.  COPPER.  Eq.  31.7. 

Sources. — Found  with  cubic  crystallization  or  massive 
at  Lake  Superior  and  in  Siberia.  The  Cornish  mines 
afford  Copper  Pyrites,  Cu^S-j-Fe2S3.  From  the  Urals 
and  from  Australia  come  blue  and  green  Carbonates,  Azu- 
rite  and  Malachite ;  from  Cuba  red  and  black  Oxides  and 
Sulphides ;  from  Chili  a  Chloride,  Atacamite. 

Properties. — Yellowish-red  metal,  hard,  very  malleable, 
ductile,  and  tenacious.  Fuses  at  1996°;  one  of  the  best 
conductors  of  heat  and  electricity ;  burns  in  chlorine  spon- 
taneously, when  in  leaf  form,  and  in  oxygen  at  a  moderate 
temperature.  Sp.  Gr.  8.9. 

Uses. — In  coinage,  alone  or  alloyed  with  nickel ;  sheath- 
ing of  ships;  in  many  pieces  of  mechanism;  forms  the 
negative  element  in  Daniel's  battery  (Fig.  150,  described 
page  98);  alloyed  with  zinc  forms  brass,  and,  with  different 
proportions  of  tin,  bronze,  bell-metal,  gun-metal,  and  spec- 


LEAD. 


215 


ulum-metal.     The  Suboxide  of  Copper,  CuaO,  is  used  to 
stain    glass     a     ruby 

color  ;   the  Black  Ox-  Fig.  150. 

ide,  CuO,  communi- 
cates a  green  color  to 
glass,  and  is  used  to 
oxidize  organic  bodies 
for  purposes  of  analy- 
sis. Sulphate  of  Cop- 
per, Blue  Vitriol  (CuO, 
S03-{-5Aq),  is  used  in 
calico  printing  and  in 
the  manufacture  of 
cupreous  pigments. 

Tests. — Green  color 
in  blowpipe  flame ; 
blue  precipitate  with 
Ammonia,  red  with 
Ferrocyanide  of  Po- 
tassium. 

Sym.  Pb.  LEAD.  Eq.  103.7. 

Sources. — Metallic  Lead  is  rarely  found  native ;  gene- 
rally occurs  as  Galena,  PbS,  which  is  worked  extensively 
in  Cornwall  and  Cumberland,  England,  throughout  Spain, 
in  Missouri,  Illinois,  Iowa,  and  Wisconsin.  It  is  also 
found  combined  with  Oxygen,  Selenium,  and  Tellurium ; 
with  Arsenic  and  Antimony;  with  Carbonic,  Phosphoric, 
Arsenic,  Yanadic,  Chromic,  Antimonic,  Molybdic,  and 
Tungstic  acids. 

Extraction  from,  Galena. — When  Galena  is  roasted  it  ab- 
sorbs Oxygen,  and  part  is  converted  into  Oxide  of  Lead  with 
evolution  of  Sulphurous  acid,  PbS-f  30==PbO-f  S02,  part 
into  Sulphate  of  Lead,  PbS+4O=PbO,S03.  When  the 
Sulphide  and  Sulphate  thus  formed  come  in  contact  with 


216  LEAD. 

fresh  Galena  in  the  furnace,  they  are  both  decomposed,  with 
the  formation  of  metallic  Lead  and  Sulphurous  acid,  2PbO-|- 
PbS=3Pb-f  S02  and  PbO,S03-f  PbS=2Pb  +  2S02. 

Properties. — A  soft,  bluish-white  metal,  of  small  malle- 
ability, ductility,  and  tenacity ;  fuses  at  620°,  and  crystal- 
lizes in  cubes  on  cooling.  Sp.  Gr.  11.36.  The  high  me- 
tallic lustre  of  freshly-cut  lead  is  speedily  lost  by  the 
formation  of  a  superficial  film  of  oxide  on  exposure  to  air ; 
but  the  formation  of  this  oxide  is  due  to  the  combined 
action  of  air  and  moisture,  dry  air  alone  or  pure  water 
alone  having  no  power  to  oxidize  lead.  All  natural 
waters  hold  in  solution  air,  uncombined  carbonic  acid, 
various  chlorides,  nitrates,  and  ammonia,  all  of  which 
favor  the  corrosion  of  lead.  But  they  also  contain  sul- 
phates, phosphates,  and  carbonates,  which  generally  coun- 
terbalance the  action  of  the  preceding  substances ;  and 
thus  free  water  contained  in  leaden  cisterns,  or  conveyed 
to  inhabitants  of  towns  through  leaden  pipes,  may  hold 
an  injurious  amount  of  the  poisonous  Oxide  of  Lead. 

Uses.  —  Metallic  lead  is  but  slightly  aifected  even  by 
boiling  sulphuric  acid,  and  is  therefore  employed  in  the 
sulphuric  acid  chambers.  Since  air  and  moisture  only 
oxidize  lead  superficially,  it  is  employed  for  cisterns, 
waters,  gutters,  roofing,  etc.  Lead,  alloyed  with  about 
^  per  cent,  of  arsenic,  to  harden  and  granulate  it,  is  the 
material  of  shot.  When  lead  is  alloyed  with  one-fourth 
its  weight  of  Antimony  it  forms  type-metal,  which  has  the 
property  of  expanding  on  solidification,  and  thus  copying 
a  mould  accurately.  Pewter,  Britannia  metal,  fusible 
metal,  and  the  soft  solder  of  tinsmiths  are  alloys  of  lead. 
Of  the  four  Oxides  of  Lead,  Pb20,  PbO,  Pb02,  and 
Pb304,  the  Protoxide,  known  as  Litharge  and  Massicot,  is 
used  to  increase  the  siccative  property  of  drying  oils. 
Dissolved  in  lime-water,  it  is  used  as  a  hair-dye :  the  lime 
partially  decomposes  the  hair,  and  the  lead  of  the  oxide, 


BISMUTH. 


217 


Fig.  151. 


by  combination  with  the  sulphur  of  the  hair,  forms  Sul- 
phide of  Lead,  which  stains  the  hair  a  permanent  black. 
When  litharge  is  roasted,  at  a  temperature  of  600°,  it  ab- 
sorbs oxygen,  and  is  converted  into  Minium,  or  Red  Lead, 
Pb3O,j,  which  is  principally  employed  in  the  manufacture 
of  flint-glass.  A  combination  of  the  Chloride  and  Oxide 
of  Lead  (PbCl,7PbO)  is  used  as  a  pigment,  under  the 
name  of  Turner's  yel- 
low. Its  soluble  salts 
form  most  delicate  tests 
for  Sulphuretted  Hy- 
drogen, which  forms 
with  them  a  black  pre- 
cipitate. This  may  be 
illustrated  in  an  amu- 
sing manner  as  fol- 
lows :  We  make  a 
drawing  on  paper  with 
a  solution  of  Acetate 
or  Nitrate  of  Lead, 
thickened  so  as  to  work 
well  with  a  little  gum. 
This  drawing  is  of 
course  invisible ;  but 
if  the  paper  is  damp- 
ened by  sponging  on 
the  wrong  side,  and 
exposed  to  HS,  escaping  from  a  tube,  it  is  rapidly  devel- 
oped. Such  a  design  as  Fig.  151  is  one  well  suited  to  this 
sort  of  "  spiritual  photograph." 


Sym.  Bi.  BISMUTH. 

Discovered  by  Agricola  in  1529. 


Eq.  208. 


Source— Found  native  in  quartz-rock  in  Saxony,  Tran- 
19 


218  URANIUM. 

sylvania,  and  Bohemia,  from  which  it  is  extracted  by 
fusion  in  iron  tubes,  placed  in  an  inclined  position,  so  as 
to  allow  the  metal  to  flow  out  from  the  lower  end. 

Properties. — A  hard,  brittle,  reddish-white  metal,  which 
fuses  at  507°,  and  crystallizes  on  slow  cooling  in  very 
obtuse  rhombohedra.  Oxidized  by  air  at  high  tempera- 
tures ;  eagerly  unites  with  Chlorine,  Bromine,  Iodine,  and 
Sulphur.  Sp.  Gr.  9.79. 

Uses. — The  alloys  of  Bismuth  with  Tin  and  Lead  melt 
easily,  and  on  cooling  expand  greatly,  for  which  reasons 
they  are  largely  employed  by  die-sinkers,  under  the  name 
of  fusible  metal,  consisting  of  5  parts  of  Bi,  3  of  Pb  and 
2  of  Sn.  This  will  melt  in  boiling  \vater.  Some  of  its 
compounds  are  used  as  pigments,  and  the  Subnitrate 
(5Pb03,  4N05-f  9HO)  as  a  cosmetic  and  in  medicine. 

Test. — Yellow  precipitate  with  Chromate  of  Potassa; 
soluble  in  Nitric  acid. 


Sym.  U.  URANIUM.  Eq.  60. 

Discovered  by  Klaproth,  1789,  in  pitchblende  (2UO, 
U203),  which  contains  nearly  80  per  cent,  of  the  Black 
Oxide  of  Uranium. 

Properties.  —  Steel-white  color ;  slightly  malleable  ; 
burns  brilliantly  in  air  at  high  temperatures;  dissolved 
by  Hydrochloric  and  Sulphuric  acids,  with  the  formation 
of  a  Protochloride,  UC1,  and  a  Sulphate,  UO,S03,  which 
is  employed  in  giving  a  Canary  color  to  glass,  and  has  the 
remarkable  power  of  rendering  it  fluorescent.  (See  pages 
58  and  87.) 


TUNGSTEN — VANADIUM — MOLYBDENUM.  219 

GROUP  Y. 

Metals  whose  Oxides  are  Weak  Bases,  or  Acids. 
Sym.  W.  TUNGSTEN.  Eq.  92. 

Discovered  by  D'Elhugart,  1181. 

Sources.  —  Found  in  wolfram,  Tungstate  of  Lime,  and 
Manganese  (MnO,W03,3FeO,W03),  and  sclieelite,  Tung- 
state  of  Lime  (CaO,W03). 

Properties. — A  very  hard,  difficultly  fusible  metal,  of  an 
iron-gray  color.  Sp.  Gr.  17.6. 

Uses.  —  Tungstic  acid,  WO3,  is  used  in  calico  printing 
and  as  an  anti-combustion  mixture  with  starch,  in  the 
royal  laundry  of  England. 

Test.  —  Treated  with  Hydrochloric  acid  and  digested 
with  Zinc,  yields  a  blue  color. 

Sym.  V.  VANADIUM.  Eq.  68.46. 

Discovered  by  Sefstrcem,  1830,  in  a  Swedish  iron  ore 
from  Taberg,  but  its  principal  ore  is  the  Yanadiate  of  Lead, 
found  in  Mexico  and  Chili. 

Properties. — Yanadic  acid  is  reduced  by  Potassium  in 
a  covered  porcelain  crucible,  Y03-f  3K=3KO-f  Y. 

Test. — When  salts  of  Yanadic  acid  are  mixed  with  tinc- 
ture of  galls  they  form  a  very  black  ink,  ineffaceable  by 
acids,  alkalies,  and  even  by  chlorine. 


Sym.  Mo.  MOLYBDENUM.  Eq.  47.88. 

Discovered  by  Hjelm,  1180. 
Source. — Molybdenite,  MoS2. 

Preparation.  —  The  ore  is  first  roasted,  MoS2-ftO= 
Mo03-f  2S02,  and  the  Molybdic  acid  so  formed  is  made  into 


220  TELLURIUM  —  ARSENIC. 

a  paste  with  oil  and  charcoal,  and  exposed  to  a  high  heat 
in  a  crucible  lined  with  charcoal,  Mo034-3C=Mo+3CO. 

Properties. — White,  brittle,  and  very  difficult  of  fusion. 
Sp.  Gr.  from  8.615  to  8.636.  Forms  two  basic  oxides, 
MoO  and  Mo02,  and  a  powerful  metallic  acid,  Mo03. 

Test. — Purple  precipitate  with  Terchloride  of  Gold. 


Sym.  Te.  TELLURIUM.  Eq.  64.2. 

Discovered  by  Klaproth,  1795. 

Sources. — Found  in  Transylvania,  rarely  native,  gene- 
rally as  a  Telluride  of  Gold,  Silver,  Bismuth,  or  Lead. 

Properties. — Sp.  Gr.  6.65.  Has  the  lustre  of  a  metal, 
but  so  closely  resembles  sulphur  and  selenium  that  it  is 
often  classed  among  metalloids. 

Sym.  As.  ARSENIC.  Eq.  75. 

Source. — Generally  occurs  as  an  alloy  with  iron,  cobalt, 
nickel,  copper,  or  tin  ;  also  as  an  Ar.seniate  of  the  above 
metals,  and,  more  rarely,  in  union  with  sulphur,  forming 
realgar,  AsS2,  and  orpiment,  AsS3. 

Preparation.  —  When  arsenical  Sulphide  of  Iron,  or 
mispickel  (FeAs,FeS2),  is  roasted  it  undergoes  oxidation, 
and  its  combined  Arsenic  is  converted  into  Arsenious 
acid,  AsO3.  The  latter  is  conducted  by  the  furnace-flues 
into  large  chambers,  where  it  condenses  as  a  white  mealy 
powder.  By  heating  this  acid  with  pulverized  charcoal  in 
a  Hessian  crucible,  upon  the  top  of  which  a  second  cru- 
cible has  been  luted,  the  reduced  metal  is  sublimed  as  a 
coating  on  the  upper  crucible. 

Properties. — In  its  chemical  properties  Arsenic  is  nearly 
allied  to  nitrogen  and  phosphorus,  but,  on  account  of  its 
brilliant  steel-gray  lustre,  its  high  specific  gravity,  and  its 
facility  in  the  conduction  of  electricity,  it  is  here  classed 


ARSENTC.  221 

among  the  metals.  Heated  to  356°,  it  gives  off  an  op- 
pressive garlicky  vapor,  which  crystallizes  on  cooling  in 
rhombohedra.  Sp.  Gr.  5.7  to  5.9. 

Uses. — A  small  quantity  of  Arsenic  is  added  to  lead 
to  produce  a  rounder  shot.  When  partially  oxidized  by 
contact  with  moist  air  it  is*  converted  into  fly-powder. 
Combined  with  Oxygen,  as  Arsenious  acid,  it  forms  sev- 
eral useful  Arsenites.  That  of  Potash  has  been  long  em- 
ployed in  medicine  under  the  name  of  Fowler's  solution. 
The  Arsenite  of  Copper  (2CuO,As03)  is  the  delicate 
Scheele's  green.  The  double  salt  of  Acetate  and  Arsenite 
of  Copper— CuO,C4H303H-3(CuO,As03)— is  also  used  as 
pigment,  and  is  known  as  Scliwunfurt  green.  Arsenious 
acid  (known  in  commerce  as  Arsenic  or  ratsbane]  is  more- 
over employed  to  prevent  smut  in  grain,  and  as  a  soap  for 
glass,  by  converting  the  Protoxide  of  Iron,  which  stains 
the  glass  green,  into  a  harmless  sesquioxide. 

Arsenic  Acid,  AsO5,  prepared  by  oxidizing  Arsenious 
add  with  Nitric  acid,  has  been  employed  as  a  substitute 
for  tartaric  and  phosphoric  acids  in  calico  printing,  but  its 
use  is  attended  with  the  same  danger  of  poisoning  to  the 
workmen  employed  as  there  is  in  every  other  application 
of  Arsenic  and  its  compounds. 

The  Bisulphide  of  Arsenic  (realgar),  AsS2,  is  an  ingre- 
dient of  the  signal-light  known  as  white  Indian  fire,  and 
the  Tersulphide  (orpiment)  is  mixed  with  Arsenious  acid 
to  form  King's  yellow. 

Tests. — Before  the  blowpipe  evolves  a  peculiar  odor  of 
garlic ;  with  ammonio-nitrate  of  silver,  As03  gives  a  yel- 
low precipitate,  AsO5  a  dull  red ;  with  ammonio-nitrate 
of  copper  As03  gives  a  green  precipitate. 

Detection  of  Arsenic. 

Marsh's  Test. — In  a  hydrogen  generator,  of  the  form  in- 
dicated (Fig.  152),  introduce  some  of  the  suspected  sub- 
19* 


222 


TITANIUM  —  TIN. 


Fig.  152. 


stance.  If  Arsenic  be  present, 
a  glass  or  porcelain  plate,  held 
in  the  burning  jet  of  hydrogen, 
will  be  coated  with  a  metallic 
mirror  of  Arsenic. 

Reincli's  Test.-—  Boil  the 
suspected  liquid,  acidified  by 
one-tenth  its  bulk  of  Hydro- 
chloric acid,  for  half  an  hour 
with  bright  copper  foil.  The 
reduced  Arsenic  will  be  depos- 
ited as  gray  metallic  crust  upon 
the  Copper. 


Sym.  Ti.  TITANIUM.  Eq.  24.33. 

Discovered  by  Klaproth,  1795. 

Sources. — Ilmenite  (FeO,Ti02)  and  rutile,  brooMte  and 
anatase,  which  are  nearly  pure  Titanic  acid,  Ti02,  occur 
ring  under  different  crystalline  forms.  Copper-colored 
cubes,  consisting  of  Cyanide  and  Nitride  of  Titanium  are 
frequently  found  in  iron  slags. 

Uses. — The  Oxide  of  Titanium  is  employed  in  painting 
porcelain  and  in  coloring  artificial  teeth. 


Sym.  Sn. 


TIN. 


Eq.  58. 


Sources. — The  only  important  ore  is  Tin-stone,  SnO2. 

Extraction. — After  the  ore  has  been  roasted  and  washed 
it  is  mixed  with  one-fifth  its  weight  of  charcoal,  and  with 
a  little  lime,  as  a  flux  to  the  flinty  gangue,  and  reduced  by 
intense  heat  in  a  reverberatory  furnace. 

Properties. — A  very  malleable,  brilliant,  white  metal, 
which  fuses  at  442°.  Sp.  Gr.  7.29.  When  a  bar  of  Tin 
is  bent  it  gives  out  a  peculiar  sound,  called  the  cry  of  Tin. 


ANTIMONY.  223 

Burns  brilliantly  in  air  at  high  temperatures,  forming  the 
Binoxide,  Sn02. 

Uses. — When  molten  Tin  is  poured  upon  the  surface  of 
sheet-iron  or  copper  it  forms  a  superficial  coating  of  alloy, 
and  the  iron  or  copper  so  coated  is  extensively  employed 
under  the  name  of  Tin-plate.  The  many  alloys  of  Tin 
have  previously  been  described  under  bismuth,  copper, 
and  zinc.  An  amalgam  of  Tin  is  employed  for  silvering 
mirrors. 

Neither  the  Protoxide,  SnO,  nor  the  Anhydrous  Binoxide 
of  Tin,  SnO2,  are  employed  in  the  arts ;  but  when  the 
Binoxide  is  combined  with  water  it  undergoes  a  remark- 
able change  of  properties,  and  forms  two  acids,  Meta- 
stannic  acid  (Sn5010,10HO),  which  is  largely  employed  in 
whitening  enamels,  and,  under  the  name  of  putty  powder, 
for  polishing  plate,  and  Stannic  acid  (HO,Sn02),  which 
forms  in  combination  with  soda,  as  Stannate  of  Soda 
(NaO,S02+4Aq),  a  much-used  mordant.  Of  the  three 
Sulphides  of  Tin,  SnS,Sn2S3  and  SnS2,  the  last  is  em- 
ployed, under  the  name  of  mosaic  gold,  in  imitating 
bronze,  and  with  electrical  machines. 


4 
Sym,  Sb.  ANTIMONY.  Eq.  120,3. 

Discovered  by  Basil  Valentine,  at  the  end  of  the  thir- 
teenth century. 

Sources.  —  Sometimes  found  native,  frequently  as  an 
alloy  with  other  metals ;  but  always  extracted  from  the 
tersulphide  of  antimony — grey  antimony  ore  SbS3. 

Properties.  —  A  brilliant,  bluish -white,  brittle  metal, 
which  fuses  at  840°.  Sp.  Gr.  6.115. 

Uses.  —  The  most  important  alloy  of  antimony  is  type- 
metal;  which  consists  of  100  parts  of  lead  and  20  of  anti- 
mony and  5  of  tin.  For  stereotyping,  Pb  100,  Sb  18,  Sn  5. 

Compounds. — Antimony  combines  with  both  three  and 


224  TANTALUM — COLUMBIUM MERCURY. 

five  equivalents  of  oxygen,  sulphur,  and  chlorine.  When 
combined  with  potassa  and  tartaric  acid,  the  teroxide,  Sb03, 
forms  tartar  emetic  (KO,SbO8,T)  ;  ground  with  linseed- 
oil,  it  is  employed  as  a  substitute  for  white  lead.  When 
an  alloy  of  zinc  and  antimony  is  dissolved  in  dilute  sul- 
phuric acid,  the  hydrogen  set  free  from  the  water  of  the 
sulphuric  acid  unites,  while  in  a  nascent  state,  with  anti- 
mony, to  form  antimoniuretted  hydrogen,  SbH3Zn8Sb-f- 
3(HO,S03)  =  3(ZnO,S03)-f-  SbH3. 

Test.  —  The  salts  of  antimony  give  an  orange-red  pre- 
cipitate of  tersulphide,  with  sulphuretted  hydrogen. 


Sym.  Ta.  TANTALUM.  Eq.  68.72 

Discovered  by  Ekeberg,  in  yttrotantalite  from  Sweden, 


1802. 


Sym.  Cb.  COLUMBIUM.  Eq.  68.8. 

Found  by  Hatchett,  in  a  black  mineral  from  Massachu- 
setts named  columbtie,  in  1801. 

GROUP   VI. 

Noble  Metals  reduced  from  their  Oxides  by  Heat  alone. 
Sym.  Hg.  MERCURY.  Eq.  100. 

Sources. — Occasionally  found  in  the  metallic  state,  but 
generally  combined  with  sulphur,  forming  cinnabar  HgS. 
By  beating,  cinnabar  gives  off  its  sulphur  as  sulphurous 
acid,  and  its  mercury  as  a  vapor,  which  is  collected  in 
condensing  chambers. 

Properties.  —  Mercury  is  the  only  metal  which  is  fluid 
at  ordinary  temperatures.  It  freezes  at  — 39°,  and  boils  at 
662°.  Heated  in  the  air  to  650°,  it  is  converted  into  the 
red  oxide ;  with  chlorine,  bromine,  and  many  metals,  it 


SILVER.  225 

combines  at  ordinary  temperatures ;  and  also  with  sulphur 
and  iodine,  if  triturated  with  them.  Sp.  Gr.  13.5. 

Uses.  —  Largely  employed  to  form  an  amalgam  with 
silver  and  gold,  in  order  to  extract  them  from  their  ores ; 
in  the  construction  of  thermometers,  barometers,  etc ;  as  a 
medicine ;  as  an  amalgam  with  tin  in  silvering  mirrors. 

Compounds. —  Oxygen,  sulphur,  chlorine,  bromine,  and 
iodine  unite  with  both  one  and  two  equivalents  of  mercury. 
Of  the  compounds  so  formed,  HgS  is  known  as  the  valu- 
able pigment  vermilion  ;  Hg2Cl,  Subchloride  of  Mercury, 
and  HgCl,  are  known  in  medicine  under  the  names  of 
calomel  and  corrosive  sublimate ;  the  Bromides  and  Iodides 
of  mercury  are  employed  in  photography. 

Tests. — With  iodide  of  potassium,  a  precipitate  first 
yellow,  then  red ;  silver-like  deposit  on  copper  foil. 

Sym.  Ag.  SILVER.  Eq.  1.08. 

Sources. — Found  native,  as  a  chloride  :  but  principally 
obtained  from  its  sulphide,  AgS.  The  latter  is  frequently 
associated  with  lead  to  form  argentiferous  galena. 

Uses.  —  Employed  in  silver  electro-plating  the  cheaper 
metals.  In  order  to  make  jewellers'-ware  and  silver  coin 
hard  enough  to  resist  wear,  it  is  alloyed  with  a  small  quan- 
tity of  copper.  The  United  States  standard  silver  consists 
of  90  per  cent,  of  sil-ver  and  10  per  cent,  of  copper. 

Nitrate  of  silver  thickened  with  gum  Arabic  and  colored 
by  India-ink  is  used  for  marking  linen  indelibly.  The  linen 
is  first  moistened  with  a  solution  of  soda,  which  precipi- 
tates the  oxide  of  silver  upon  the  fibre  of  the  goods. 

Photographs  are  prepared  by  first  immersing  the  papers 
in  an  alkaline  chloride,  and  afterwards  in  a  bath  of  nitrate 
of  silver.  A  deposit  of  chloride  of  silver  is  thus  formed, 
which  blackens  whenever  exposed  to  the  light,  and  pro- 
duces the  negative  of  the  picture.  The  iodides  and  bro- 
mides of  silver  are  also  employed  in  photography ;  and 


226  GOLD — PLATINUM. 

the   nitrate,  under  the   name   of   lunar  caustic,  as    an 
escharotic. 

Test.  —  Hydrochloric  acid  or  a  soluble  chloride,  precip- 
itates a  dense  white  cloud  of  chloride  of  silver,  quickly 
changing  to  violet  by  exposure  to  the  light. 

Sym.  AU.  GOLD.  Eq.  197. 

Sources.  —  Found  crystallized  in  tubes  or  octahedra,  or 
in  masses  called  nuggets. 

Properties. — Most  malleable  of  metals  ;  one  of  the  best 
conductors  of  heat  and  electricity;  fuses  at  2016°.  Un- 
affected by  any  of  the  acids  alone,  but  dissolved  by  a 
mixture  of  1  part  of  nitric  acid  with  4  parts  of  hydro- 
chloric acid — aqua  regia.  Sp.  Gr.  19.34. 

Uses. — In  the  state  of  powder,  in  painting  porcelain,  etc. 
Alloyed  with  copper,  it  is  sufficiently  hard  for  jewellers'- 
ware  and  coin.  Employed  to  color  glass  a  deep  red.  The 
cyanide  of  gold  and  potassium  is  used  for  electro-gilding. 

Test. — A  mixture  of  protochloride  and  bichloride  of  tin 
precipitates  from  salts  of  gold  the  Purple  of  Cassius ; 
oxalic  acid  with  heat  a  brown  precipitate  of  metallic  gold. 

Sym.  Pt.  PLATINUM.  Eq.  98.7. 

Sources. — Platinum,  Palladium,  Rhodium,  Osmium  Ru- 
thenium, and  Iridium  are  generally  found  associated  to- 
gether in  the  form  of  coarsely  rounded  grains. 

Properties. — Very  lustrous,  ductile,  tenacious,  white 
metal,  fusible  only  by  the  voltaic  battery  or  oxyhydrogen 
blowpipe.  Sp.  Gr.  21.5. 

Uses. — Owing  to  its  infusibility,  and  its  power  of  resisting 
alkalies,  and  other  chemical  reagents,  platinum  is  largely 
employed  as  the  material  of  crucibles  and  stills.  Those 
intended  for  the  concentration  of  sulphuric  acid  sometimes 
weigh  upwards  of  1000  ounces.  By  ignition  of  the  double 
chloride  of  platinum  and  ammonium,  metallic  platinum 


PALLADIUM. 


227 


Fig.  153. 


may  be  obtained  in  a  very  finely  divided  state,  known  as 
platinum  sponge.  This  substance  has  a  very  strong  ad- 
hesion for  gases ;  and  it  will  condense  a  mixture  of  them 
to  such  an  extent  as  to  cause  a  chemical  combination. 
Thus,  if  a  jet  of  hydrogen  is  directed  upon  a  piece  of  this 
substance  in  the  air,  the  union 
of  the  H  with  0  from  the  air, 
will  be  so  energetic  as  first  to 
heat  the  Platinum  sponge  red- 
hot,  and  then  ignite  the  hy- 
drogen jet.  This  action  is 
applied  to  the  useful  purpose 
of  procuring  a  light  rapidly, 
in  Dobereiner's  lamp  (Fig. 
153).  The  jet  of  hydrogen, 
when  turned  on,  heats  the  pla- 
tinum sponge  in  the  little  box, 
f,  is  itself  ignited,  and  so  serves 
to  light  a  taper,  or  the  like. 

Even  massive  platinum 
possesses  alike  power.  Thus 
a  wire  of  this  metal  coiled  over  the  wick  of  a  spirit-lamp, 
as  in  Fig.  154,  will  continue  to  glow  by  causing  a  slow 
combustion  of  the  alcoholic  vapor  after  the  flame  has 
been  extinguished.  This  is  called  the  "flameless  lamp." 


Fig.  154. 

Sym.  Pd.        PALLADIUM.         Eq.  53,3. 

Discovered  by  Wollaston,  1803. 

Sources. — Forms  from  one-third  to  one 
per  cent,  of  platinum  ores. 

Properties.  —  A     hard,    ductile,    white 
metal,  very  difficult  of  fusion.    Sp.  Gr.  11.4. 

Uses.  —  For  graduated  scales,  and  as  an    alloy  with 
silver,  it  is  employed  by  dentists. 


228  ORGANIC    CHEMISTRY. 

Sym.  Ir.  IRIDIUM,  Eq.  99. 

•  Descatils  and  Tenant,  1804.     Sp.  Gr.  21.15. 

Properties.  —  Yery  brittle,  hard,  white  metal,  fusible 
only  by  the  oxyhydrogen  blowpipe,  and  voltaic  current. 
It  is  the  heaviest  of  elements.  Alloyed  with  osmium,  as 
iridosmine,  it  is  used  for  pointing  pens.  Its  salts  assume, 
when  in  solution,  beautiful  colors,  from  which  property, 
the  name  iridium  (from  Iris,  the  rainbow)  is  derived. 


Sym.  Os.  OSMIUM.  Eq.  99.6. 

Tenant,  1803.     Sp.  Gr.  21.4. 

Properties. — A  white,  very  brittle  metal.  It  forms  no 
less  than  five  compounds  with  oxygen,  and  four  with 
chlorine. 

Sym.  Ru.  RUTHENIUM.  Eq.  52.2. 

Klaws,  1845.     Sp.  Gr.  11.2.     Most  infusible  of  metals. 


Sym.  Rh.  RHODIUM.  Eq.  52.2. 

Wollaston,  1804.  Sp.  Gr.  12.1.  A  white,  very  hard 
metal,  scarcely  fusible  before  the  oxyhydrogen  blowpipe. 

ORGANIC  CHEMISTRY. 

Organic  Chemistry  treats  of  those  organized  bodies 
which  have  been  formed  under  the  influence  of  the  vital 
force,  and  of  the  organic  compounds  which  can  be  derived 
from  organized  bodies  by  the  action  of  chemical  reagents. 

Both  classes  of  substances  above  referred  to,  are  dis- 
tinguished from  inorganic  substances  in  several  ways : 

1st.  The  mass  of  organic  bodies  consists  of  only  six,  out 


ORGANIC    CHEMISTRY.  229 

of  the  sixty-four  elements  ;  viz.,  carbon,  hydrogen,  oxygen, 
nitrogen,  and,  to  a  lesser  extent,  sulphur  and  phosphorus. 

2nd.  But  carbon,  hydrogen,  oxygen,  and  nitrogen,  com- 
bine in  so  many,  and  such  high  proportions,  that  they 
alone,  form  a  vastly  greater  number  of  bodies  than  is  met 
with  in  inorganic  chemistry. 

3rd.  While  inorganic  compounds  are  formed  by  the 
pairing  together  of  elements,  or  of  binaries,  or  of  ter- 
naries, with  each  other  to  form  substances  possessed  of  a 
certain  symmetry  of  constitution,  no  such  regularity  is 
observable  in  organic  chemistry. 

4th.  Natural  affinities  seem  often  to  be  overruled  by 
vital  force,  and  organic  compounds  are  formed  in  oppo- 
sition to  the  ordinary  laws  of  chemistry. 

5th.  It  thus  happens  that  organized  bodies  are  com- 
paratively unptable,  and  prone  to  decomposition  after  the 
vital  force,  which  created  them,  has  ceased  to  act. 

6th.  One  element  may  frequently  be  substituted  for 
another,  without  altering  the  essential  characteristics  of 
an  organic  compound. 

The  substances  met  with  in  organic  chemistry  are  most 
conveniently  treated  of  under  the  following  heads  : 

I.  Saccharine  and  Amylaceous  Bodies.  —  Mostly  nu- 
tritious substances  with  feeble  affinities.     They  are  com- 
posed of  24  equivalents  of  carbon,  united  with  different 
proportions  of  oxygen  and  hydrogen.     From  them  are 
derived  the  Alcohols  and  Ethers. 

II.  Ethyl,  Methyl,  etc. — Compound  radicals  resembling 
in  their  chemical  relations  hydrogen  and  the  metals. 

III.  Vegetable  Acids. 

IV.  Vegetable  Bases  : 

(a)  Those  found  in  nature. 

(b)  Those  formed  artificially. 

V.  Oils: 

(a)  Fixed  Oils  or  Fats. 
20 


230 


STARCH. 


(b)  Essential  or  Volatile  Oils. 

VI.  Cyanogen  —  a  compound  radical  which  resembles 
chlorine  in  its  relations  —  and  its  compounds. 

VII.  Organic  Coloring-Principles. 

VIII.  Albuminous  Bodies. 


I.  SACCHARINE  AND  AMYLACEOUS  BODIES. 
1.  Starch—  C^H^O*. 

Sources.  —  The  grains,  roots,  and  stems  of  plants.  It 
occurs  in  small,  rounded  grains,  which  vary  greatly  in 
size  and  appearance.  Those  of  the  tons  les  mois  are 
about  Tjifl  of  an  inch  in  diameter;  and  those  of  wheat, 
y^ooth.  Each  grain  is  inclosed  in  a  thin  envelope,  which 
is  unaffected  by  cold  water,  but  ruptured  by  the  expansion 
of  the  starchy  matter,  on  applying  heat. 

Figure  155  represents  some  starch  grains  of  the  potato, 
as  seen  under  the  microscope,  by  ordinary  light. 


Fig.  155. 


Fig.  156. 


Figure  156  shows  the  appearance  of  the  same,  when 
viewed  by  polarized  light,  as  indicated  in  pages  65  and 
66,  a  black  cross  being  here  developed  on  each  grain. 

Figure  151  shows  one  of  these  grains,  after  it  has  been 
boiled,  as  viewed  under  a  powerful  microscope. 

Preparations.  —  In  order  to  free  the  starch  granules 
from  gluten  and  other  substances  contained  in  the  seeds, 


GUM  —  LIGNINE.  231 

the  latter,  after  being  mashed,  are  washed  upon  a  cloth 
sieve  with  water  ;  the  gluten  remains  behind. 

Properties. — An  insipid,  white  solid,  insoluble  in  cold, 
but  slightly  soluble  in  boiling  water.  By  exposure  for  a 
length  of  time  to  a  temperature  of  400°,  by  gentle  heat- 
ing in  acidulated  water,  or  by  the  action  of  diastase  —  a 
nitrogenized  body  formed  from  the  gluten  of  germinating 
seeds  —  starch  undergoes  a  peculiar  change,  and  the  sub- 
stance so  formed,  and  which  is  known  under  the  name  of 
Dextrine  or  British  Gum,  is  capable  of  solution  in  cold 
water.  It  is  employed  in  the  manufacture  of  envelopes, 
for  dressing  chintzes,  and  other  cotton  goods,  in  the  fast- 
ening of  mordants,  etc. 

Arrow-root,  tapioca,  and  sago,  are  varieties  of  starch. 

Test.  —  Iodine  forms  a  beautiful  blue  compound  with 
starch,  which  is  insoluble. 

2.  Gum  —  C^H^O^. 

A  term  applied  to  a  number  of  substances  which  exude 
from  the  bark  of  trees,  and  form  glassy,  tasteless,  and 
inodorous  masses,  generally  of  a  globular  form.  Dis- 
solved in  water,  they  form  mucilage,  which  is  used  as  a 
substitute  for  paste.  Gum  Arabic,  Gum  Senegal,  and 
Gum  Tragacanth,  are  the  important  varieties. 

By  boiling  with  Sulphuric  acid,  Gum  Arabic  yields  sugar 
— with  nitric  acid,  mucic  acid. 

3.  Lignine  —  C^H^CV 

Modifications. — Woody  Fibre  ;  Cellulose. 

Sources.  —  Found  under  many  modifications  :  some- 
times it  can  be  used  as  food ;  as  the  pulp  of  roots, 
esculent  plants ;  at  others  it  is  indigestible  ;  wood  ;  shells 
of  nuts :  it  is  light  and  porous  in  elder  pith  or  cork ;  soft 
and  pliable  in  hemp  and  cotton  fibre.  Fig.  158  shows 
Lignine  of  wood,  as  seen  under  the  microscope. 


232  LIGNINE. 

Properties. — Tasteless,  insoluble  in  water  and  alcohol, 
and  incapable  of  nutrition.  At  low 
temperatures,  strong  oil  of  vitriol  con- 
verts it  into  dextrine,  and  finally  into 
glucose.  It  is  not  colored  by  iodine. 

By  the  action  of  equal  parts  of  the 
strongest  nitric  and  sulphuric  acids,  it 
is  changed  into  a  very  explosive  body, 
gun-cotton,  or  pyroxyline.  It  has  two 
modifications ;  the  one,  explosive,  is  insoluble  in  a  mix- 
ture of  alcohol  and  ether;  the  other  is  readily  soluble, 
collodion.  The  latter  is  largely  employed  in  preparing 
photographic  plates,  and  in  surgery.  This  change  is  not 
well  understood,  but  it  is  supposed  that  the  elements  of 
Hyponitric  acid  are  substituted  for  several  equivalents  of 
hydrogen;  thus,  to  form  gun-cotton,  C2J:I20020-}-4NO5= 
C24H16(NO4)4020-f4HO;  to  form  collodion,  C^HaAo-f 
6N05=C24H14(N04)6020+6HO. 

By  acting  on  starch,  grape-sugar,  mannite,  gum,  and 
dextrine",  with  nitric  acid  of  specific  gravity  1.5,  they  are 
converted  into  a  transparent,  colorless  jelly,  known  as 
xyloidin.  Paper  so  treated  acquires  the  appearance  of 
parchment,  and  great  combustibility. 

When  wood  is  kept  in  dry  air  or  under  water  it  under- 
goes no  change,  but  exposed  to  air,  in  presence  of  moisture, 
it  absorbs  oxygen,  and  experiences  a  slow  decay,  erema- 
causis,  with  the  evolution  of  carbonic  acid  and  water. 
The  fertility  of  the  soil  depends  in  great  measure  upon 
the  presence  of  decaying  vegetable  matter — humus,  geine, 
ulmine — and  the  constant  liberation  of  carbonic  acid  and 
water. 

When  vegetable  matter,  such  as  the  roots  of  plants, 
decays  under  water,  and  consequently  out  of  contact  with 
air,  peat  is  first  formed,  and  afterwards,  by  the  heat  de- 
veloped during  decomposition  and  by  pressure,  changed 


CREOSOTE — PARAFFINE.  233 

into  lignite,  and  finally  into  coal.  Bituminous  substances, 
like  naphtha,  petroleum,  asphaltum,  etc.,  have  probably 
been  formed  from  plants  or  marine  animals  by  slow  decay 
under  water. 

When  wood  is  subjected  to  destructive  distillation  it 
gives  off  illuminating  gas  and  many  other  hydrocarbons, 
along  with  water,  acetic  pyroligneous  acids,  creosote,  pyr- 
oxylic  spirit,  tar,  etc. 

Creosote — C28H1604.  A  colorless,  oily,  transparent  liquid, 
which  boils  at  39*7°.  It  has  a  burning  taste  and  a  smell 
like  burned  meat.  It  is  highly  antiseptic,  and  it  is  owing 
to  the  presence  of  Creosote  in  tar,  smoke,  and  pyroligneous 
acid  that  these  substances  have  preservative  properties. 
Used  both  internally  and  externally  in  medicine. 

When  tar  is  distilled,  a  light  and  heavy  oil  passes  over 
and  a  hard  residuum,  pitch,  remains.  The  principal  con- 
stituent of  the  light  oil  is  Eupione,  C5HG,  of  the  heavy 
oil,  Paraffine,  C20H21. 

Paraflme  is  a  tasteless,  inodorous,  white  solid.  It  is 
insoluble  in  water,  but  dissolves  freely  in  ether  and  oils. 
In  consequence  of  its  perfect  indifference  to  the  strongest 
alkalies  and  acids,  it  has  derived  its  name  from  the  two 
Latin  words  parum  and  affinis,  "  without  connection." 

On  distilling  bituminous  coal,  illuminating  gas  (which 
consists  mainly  of  light  and  heavy  carburetted  hydrogen), 
carbonic  acid,  sulphuretted  hydrogen,  salts  of  ammonia, 
etc.,  and  a  viscid,  resinous  liquid,  called  coal-tar,  are 
formed. 

Coal-tar  yields  on  distillation  a  very  volatile,  inflamma- 
ble oil,  which  has  been  largely  employed  in  Germany, 
France,  England,  and  in  this  country,  before  the  discovery 
of  petroleum,  for  illuminating  purposes.  It  has  likewise 
been  used  extensively  as  a  solvent  for  caoutchouc,  in  the 
manufacture  of  water-proof  goods. 

This  coal-tar  oil  is  found,  by  treatment  with  acids  and 
20* 


234  SUGARS. 

alkalies,  to  contain  three  classes  of  bodies:  1st.  Sub- 
stances having  a  basic  reaction,  picoline,  aniline,  and 
leucoline;  2nd.  Acids,  of  which  the  most  important  is 
carbolic  acid,  or  phenol;  and  3rd.  Neutral  Hydrocar- 
bons, some  of  which  are  liquid,  as  toluol,  cymol,  benzol, 
and  others  solid,  as  naphthalin  and  paranaphthalin. 

Naphthalin,  C20H8,  separates  in  colorless,  crystalline 
plates  from  the  oil  which  comes  over  last  in  the  distilla- 
tion of  coal.  It  melts  at  176°,  boils  at  413°,  and,  heated 
to  a  still  higher  point,  burns  with  a  red,  smoky  flame.  It 
has  the  same  composition  as  paranaphthalin,  from  which 
it  mainly  differs  in  being  freely  soluble  in  alcohol. 

4.  Sugars. 

There  are  several  varieties  of  sugar,  all  of  which  are 
sweet  to  the  taste,  soluble  in  water,  and  convertible  into 
alcohol  by  fermentation.  The  most  important  are  : — 

1st.  Cane-sugar— CMUW0M. 

Sources.  —  Chiefly  obtained  from  the  sugar-cane;  also 
found  in  the  sap  of  the  sugar-maple,  in  the  juices  of  the 
beet  and  other  roots,  and  the  stalks  of  Indian-corn. 

Preparation. — After  its  juices  have  been  expressed  from 
the  plant,  they  are  evaporated  to  a  thick  syrup,  from  which 
the  sugar  crystallizes  on  cooling.  What  remains  is  treacle, 
or  molasses. 

Properties. — White,  inodorous,  very  sweet,  and  soluble; 
by  slow  evaporation  it  may  be  made  to  crystallize  in 
prisms — rock-candy.  It  melts  at  356°,  and  forms,  on  cool- 
ing, barley-sugar ;  at  a  temperature  of  420°,  it  gives  up 
four  atoms  of  water,  and  is  converted  into  caramel, 
C^His^is- 

2nd.  Grape-sugar — C24H18018.    Glucose. 

Sources.  —  Grapes,  many  other  sweet  fruits,  and  the 
solid  part  of  honey. 

Preparation.  —  The  juice  of  grapes  is  first  freed  from 


FERMENTATION.  235 

acid  by  neutralizing  it  with  chalk,  then  boiled  down  to  a 
syrup,  clarified,  and  crystallized.  Also  prepared  by  con- 
version of  starch  or  lignine,  page  232. 

Properties. — Not  by  any  means  as  sweet  or  soluble  as 
cane-sugar. 

Test.  —  Grape-sugar  instantly  precipitates  suboxide  of 
copper,  from  a  solution  of  sulphate  of  copper  containing 
potassa,  while  cane-sugar  slowly  affects  it. 

FERMENTATION. 

This  term  is  applied  to  a  decomposition  of  an  organic 
body,  resulting  from  the  decomposing  force  exerted  by  an- 
other organic  substance,  called  a,  ferment,  which  is  itself 
in  process  of  decomposition.  The  molecular  movement 
that  is  taking  place  among  the  particles  of  the  ferment 
appears  to  be  communicated  to  the  fermentable  sub- 
stances with  which  it  is  in  contact,  and  causes  them  to 
break  up  into  their  simpler  constituents. 

There  are  many  ferments :  yeast  (which  is  the  frothy 
matter  that  forms  on  beer  and  other  liquids  in  process  of 
fermentation),  blood,  albumen,  caseine,  and  juices  of  many 
plants,  and  other  putrescent  matters.  They  all  contain 
nitrogen,  and  derive  from  it  their  peculiar  proneness  to 
decomposition.  So  likewise  there  are  several  kinds  of  fer- 
mentation, distinguished  as  the 

(a)  Lactic.  —  When  putrid  cheese  is  mixed  with  water 
and  sugar,  the  caseine  contained  in  the  former  substance 
produces  fermentation,  and  the  sugar  is  converted  into 
Lactic  acid,  C6H505,HO,  carbonic  acid,  and  water. 

(b)  Butyric. — If  this  fermentation  is  allowed  to  proceed, 
the  lactic  acid  disappears  and  Butyric  acid  (C8H703,HO) 
is  found  in  its  place  ;  thus,  C24H28028==4HO+8H-f8C02-f 
2(C8H703,HO). 

(c)  Viscous.  —  So  also,  when  the  juice  of  beets  is  ex- 
posed to  a  temperature  of  100°  for  some  time,  in  contact 


236  WINE-ALCOHOL. 

with  air,  it  is  converted  into  lactic  acid  and  a  viscous  mu- 
cilaginous substance  resembling  ^lim  Arabic. 

(d)  Vinous  or  Alcoholic. — Pure  grape-sugar  undergoes 
no  change  in  or  out  of  contact  with  air,  but  when  mixed 
with  yeast  it  is  rapidly  converted  into  water,  carbonic 
acid,  and  alcohol,  C,H50,HO ;  thus,  C24H28028=4HO+ 
8C02+4(C4H50,HO). 

Alcohols  and  their  Derivatives. 

1.  Wine-Alcohol. 

(a*)  Ether.     Action  of  acid  on  alcohol. 

(6)  Aldehyde,  Acetal,  Acetic  Acid,  and  Acetone.  Ac- 
tion of  oxygen  on  alcohol. 

(c)  Chloral,  Mercaptan.  Action  of  chlorine  and  sul- 
phur on  alcohol. 

2.  Methylic  Alcohol;  Wood  Spirit, 
(a)  Wood-ether. 

(6)  Formic  Acid. 

3.  Propylic,  Butylic,  and  Amylic  Alcohol;  their  homo- 
logues  and  derivatives. 

1.  Wine- Alcohol  —  C4H50,HO.  The  alcohol  obtained 
by  fermentation,  as  above  described,  is  very  dilute.  By 
successive  distillations,  however,  it  may  be  rectified  until 
it  contains  but  10  per  cent,  of  water.  To  obtain  absolute 
or  pure  alcohol,  common  alcohol  must  be  thoroughly  mixed 
with  half  its  weight  of  quicklime,  and  the  spirit  distilled 
from  the  mixture  by  the  heat  of  a  water-bath. 

Properties. — Pure  alcohol  is  a  limpid,  colorless  liquid, 
of  a  penetrating  smell  and  agreeable  taste.  Its  specific 
gravity  at  60°  is  0.794.  It  boils  at  173°,  giving  off  a  vapor 
which  is  very  inflammable,  and  burning  with  a  pale,  smoke- 
less, hot  flame.  It  has  never  been  frozen,  but  at  a  tem- 
perature of  — 146°  becomes  thick  and  tenacious,  like 
melted  wax.  In  solvent  powers,  it  is  inferior  to  water 
only,  and  dissolves  many  substances  totally  insoluble  in 


ETHER. 


23T 


water,  like  the  resins.  Not  only  is  a  great  number  of 
vegetable  bodies,  like  the  alkaloids,  essential  oils,  etc., 
soluble  in  alcohol,  but  also  the  mineral  alkalies  and  many 
salts.  The  process  of  malting,  brewing,  and  bread-making 
depend  upon  the  formation  of  alcohol. 

O)  Ether— C4H50. 

Preparation. — A  mixture  is  made  of  8  parts  by  weight 
of  concentrated  Sulphuric  acid  and  5  parts  of  Alcohol,  of 
sp.  gr.  0.834,  and  heated  in  flask  A.  When  its  temper- 

159. 


ature  has  risen  to  300°,  the  heat  is  regulated  so  as 
constantly  to  maintain  that  temperature.  Under  these 
circumstances  Alcohol  and  Sulphuric  acid  combine,  and 
the  Sulpho-vinic  acid  thus  formed  is  afterwards  decomposed 
into  Sulphuric  acid  and  Ether,  C4H50,HO-f  2(HO,S03)= 
(C4H50,2S03,HO)-f-HO)  and  (C4H50,2S03,HO)  + H0= 
C4H50-f2(HO,S03).  The  Ether  and  water  vapor  con- 
dense into  the  inner  tube,  around  which  cold  water  is 
kept  flowing  (in  at  d  and  out  at  g),  and  are  collected  in  a 
vessel  placed  at  its  lower  end.  The  process  may  be  made 


238  ALDEHYDE  —  ACETAL  —  ACETIC    ACID. 

continuous,  if  alcohol  is  supplied  to  A;  for  the  acid  serves 
merely  to  break  up  the  alcohol  which  is  constantly  flowing 
into  the  flask,  and  at  the  end  of  the  operation  remains 
behind,  while  the  ether  distills  over  into  the  condenser. 

Properties. — Owing  to  its  mode  of  formation,  commer- 
cial Ether  thus  obtained  is  termed  Sulphuric  Ether.  It  is 
a  colorless,  limpid  liquid,  of  fragrant,  intoxicating  odor, 
and  pungent  taste.  At  60°  its  density  is  0.12  ;  it  boils  at 
96°,  and  remains  liquid  under  the  severest  cold.  Ether 
dissolves  phosphorus,  a  few  salts,  most  oils  and  fats,  and 
some  other  organic  compounds.  When  exposed  to  air, 
Ether  absorbs  oxygen  and  is  converted  into  Acetic  acid, 
C4H303,HO.  Transmitted  through  a  red-hot  tube,  it  is 
resolved  into  light  and  heavy  Carburetted  Hydrogen  and 
Aldehyde,  C4H30,HO.  Its  vapor,  when  inhaled  with  air, 
produces  insensibility  to  pain. 

(b)  Products  of  the  Oxidation  of  Alcohol. 

Aldehyde  is  a  thin,  colorless  fluid,  of  a  suffocating,  ethe- 
real odor;  density  O.T92  ;  boiling  point  T2° ;  and  burns  with 
a  pale  flame.  It  is  soluble  in  water,  alcohol,  and  ether; 
dissolves  sulphur,  phosphorus,  and  iodine,  and  has  such 
an  affinity  for  oxygen  that  it  reduces  many  metallic  salts. 

Acetal,  C12H1404,  is  a  colorless  liquid,  formed  by  the 
slow  action  of  moistened  platinum  black,  upon  the  vapor 
of  alcohol  diffused  through  a  bell-glass,  to  which  air  has 
free  access.  By  prolonging  the  action  of  platinum  black, 
Acetal  absorbs  still  more  oxygen,  and  is  converted  first 
into  aldehyde,  and  finally  into  acetic  acid. 

Acetic  Acid,  C4H303,HO,  is  manufactured  in  Germany 
by  causing  a  mixture  of  dilute  alcohol  and  yeast  to  flow 
over  wood-shavings,  which  are  exposed  in  a  current  of  air 
in  a  cask  pierced  with  holes.  The  best  vinegar,  however, 
is  made  by  the  natural  souring  of  wine  when  exposed  to 
the  air,  C4H50,HO  +  40  =  C4H303,HO-f  2HO.  Pyrolig- 


ACETONE.  239 

neous  acid,  when  distilled,  yields  an  impure  acetic  acid, 
which  is  extensively  employed  in  calico  printing. 

Properties. — When  concentrated  it  is  a  colorless  liquid, 
of  a  pleasant,  penetrating  odor,  and  extremely  sour  taste. 
It  boils  at  240°,  giving  off  inflammable  vapor;  cooled 
below  60°,  it  solidifies  in  large  transparent  crystals;  at 
60°  its  density  is  1.06.  It  readily  mixes  with  water,  al- 
cohol, and  ether,  and  dissolves  camphor  and  several  resins. 
All  the  Acetates  are  soluble.  The  most  important  are : — 

Acetate  of  Lead,  PbO,C4H303-f-3HO,  Sugar  of  Lead 
is  formed  by  dissolving  Litharge  in  Acetic  acid.  It  is  a 
powerful  poison.  Employed  in  analysis,  and  externally 
in  medicine.  Besides  this  neutral  salt,  there  are  various 
basic  Acetates,  as  2Pb03C4H303  and  3PbO,C4H303-f  HO. 
The  latter  crystallize  in  needles,  from  a  solution  of  7  parts 
of  litharge  and  10  parts  of  sugar  of  lead  digested  in  30 
parts  of  water.  It  is  used  in  the  proximate  analysis  of 
organic  compounds  and  in  pharmacy  under  the  name  of 
Goulard's  Extract  of  Lead. 

Acetate  of  Copper,  CuO,C4H303-f  HO,  Distilled  Verdi- 
gris is  obtained  in  dark-green  crystals  from  a  filtered 
solution  of  verdigris  in  hot  acetic  acid.  It  is  used  as  a 
pigment.  Verdigris  is  a  mixture  of  subacetates,  procured 
by  covering  copper  plates  with  pyroligneous  acid  or  the 
refuse  of  grapes  in  wine-making. 

Acetate  of  Alumina,  A1203,3(C4H303),  is  obtained  by  de- 
composing a  solution  of  Sugar  of  Lead  by  Alum.  Used 
as  a  mordant. 

Ghloracetic  Acid,  C4C1303,HO,  is  formed  by  exposing 
crystals  of  Acetic  acid,  placed  under  a  bell-jar  filled  with 
chlorine,  to  the  direct  rays  of  the  sun.  Three  atoms  of 
Hydrogen  are  replaced  by  3  atoms  of  Chlorine ;  thus, 
C4H303,HO  +  6Cl=C4Cl303,HO-f  3HC1.  It  closely  resem- 
bles acetic  acid,  and  forms  analogous  chloracetates. 

Acetone,   C3H30,  Pyroacetic   Acid  is   an   inflammable 


240  METHYLIC    ALCOHOL. 

liquid  obtained  by  destructive  distillation  of  metallic  ace- 
tates ;   thus,  2(PbOAH808) 


(c)  Action  of  Chlorine  and  Sulphur  on  Alcohol. 

Chloral  —  C4HCLO2  .  When  dry  chlorine  is  passed  into 
absolute  alcohol,  aldehyde  is  first  formed,  and  hydro- 
chloric acid.  By  continuing  the  process,  still  more 
hydrogen  is  replaced  by  chlorine,  and  at  last  chloral  is 
formed;  thus,  C4H602+2C1=C4H402  +  2HC1,  and  C4H4O2 
+  6C1=C4HC1302+3HC1.  It  is  an  oily  liquid,  of  a 
peculiar  odor,  which  brings  tears  to  the  eyes,  specific 
gravity  1.5,  and  boils  at  201°.  Bromine  is  likewise 
absorbed  by  alcohol,  to  form  bromal,  C4HBr302,  and  both 
are  decomposed  by  caustic  alkalies,  with  the  production 
of  a  formate  of  the  base,  and  chloroform  or  bromoform  ; 
thus,  KO,HO  +  C4HC1302=KO,C2H03  +  C2HC13. 

In  like  manner  by  the  action  of  chlorine  on  light  hy- 
drochloric ether,  C4H5C1,  one  atom  of  hydrogen  after 
another  may  successively  be  replaced  by  chlorine,  until 
finally  in  the  fifth  distinct  compound  thus  formed,  sesqui- 
chloride  of  carbon,  C4C16,  no  hydrogen  remains. 

Mercaptan  —  C4H6S2,  is  a  limpid  liquid  obtained  by 
replacing,  not  the  hydrogen  in  alcohol,  but  oxygen,  with 
its  congener,  sulphur. 

2.  Methylic  Alcohol—  C2H402==C2H30,HO. 

(a)  Preparation.  —  Among  the  products  of  the  destruc- 
tive distillation  of  wood  is  pyroxylic  spirit  (from  rtvp  fire, 
and  ffufcov  wood),  or  as  it  is  more  properly  designated 
methylic  alcohol. 

Properties.  —  When  purified  by  successive  distillations 
from  chloride  of  calcium  and  lime,  it  is  a  colorless  liquid, 
with  a  density  of  0.798,  which  boils  at  152°,  and  burns 
freely  in  a  lamp.  It  is  miscible  with  water,  alcohol,  and 
ether,  and  dissolves  freely  most  resins.  It  has  been  used 
in  medicine,  under  the  name  of  wood  naphtha. 


FORMIC    ACID. 


241 


(6)  When  wood-spirit  is  exposed  to  the  action  of  moist- 
ened platinum  black,  under  a  bell-jar,  to  which  there 
is  free  access  of  air,  oxygen  is  absorbed,  and  formic  acid 
(so  called  from  its  occurrence  in  the  bodies  of  red  ants, 
formica  rufa)  is  formed;  thus,  C4H402-|-40=C2H204-|- 
2HO. 

Formic  Acid  —  C2H204,  is  a  clear  liquid  of  acid  taste, 
pungent  odor,  density  1.24,  and  when  dropped  upon  the 
skin  quickly  blisters  it.  It  boils  at  212°,  producing  an 
inflammable  vapor,  and  freezes  at  32°.  The  alkaline  for- 
mates are  used  in  the  reduction  of  metallic  oxides. 

3.  It  will  be  seen  on  inspection,  that  methylic-alcohol, 
C2H402,  and  wine-alcohol,  C4H602;  wood-ether,  C2H3O, 
and  sulphuric  ether,  C4H50 ;  formic  acid,  C2H204,  and 
acetic  acid,  C4H404,  all  differ  from  one  another  by  C2H2. 
Now,  bodies  which  vary  by  C2H2,  or  by  a  multiple  of  it, 
are  termed  homologous,  and  there  number  is  very  great. 
If  we  add  C2H2  to  the  alcohols,  ethers  and  acids  pre- 
viously mentioned,  we  shall  get  long  series  of  new  alco- 
hols and  acids,  many  of  whose  members  are  already 
known  to  us ;  thus, 


ALCOHOLS. 

ACIDS. 

ETHERS. 

Methylic, 

C2H,02. 

Formic, 

C2H2CU. 

Methylic, 

C2H30. 

Vinic, 

CJI602. 

Acetic, 

C4H404. 

Common, 

C4H50. 

Propylic, 

C6H802. 

Prop  ionic, 

C6H604. 

C6H70. 

Butylic, 

C8Hi002. 

Butyric, 

C8H804. 

Butylic, 

C8H90. 

Amylic, 

Ci0Hi202. 

Valeric, 

CioHio04. 

Amylic, 

CioHnO. 

Ci2Hu02. 

Caproic, 

Ci2Hi2Oi. 

CnHi602. 

uEnadthylic, 

Ci4-IIi404. 

Caprylic, 

Ci6Hi802. 

Caprylic, 

CigHieO^. 

Caprylic, 

CieHnO. 

Besides  the  wine-alcohol  obtained  in  the  fermentation 
of  saccharine  matters,  various  acrid  volatile-oils,  called 
fusel-oils,  are  formed,  which  likewise  yield  on  distillation 
alcoholic  liquids.  The  fusel-oil  obtained  by  fermenting 
the  husk  or  marc  of  the  grape,  for  example,  yields  butyl- 
alcohol,  C6H802,  the  fusel-oil  of  beet-root  sugar  produces 
21 


242  ETHYL — METHYL. 

propyl-alcoho],  C8H1002,  and  that  of  potato-brandy,  amyl- 
alcohol,  C10H1202. 

As  methyl-alcohol,  and  wine-alcohol,  yield  formic  acid 
and  acetic  acid  by  oxidation,  so  also  propyl,  butyl,  and 
amyl-alcohol,  are  converted  by  absorption  of  oxygen  into 
propionic,  butyric,  and  valeric  acids ;  thus,  C4H602  (wine- 
alcohol)-MO=2HO+ C4H404  (acetic  acid),  and  C10H1202 
(amyl-alcohol) +  4O  =  2HO-f-C10H1004  (valeric  acid). 

By  treatment  with  strong  acids,  the  alcohols  may  be 
converted  into  ethers,  as  described  on  page  237. 

As  we  pass  from  the  lower  members  of  these  homo- 
logous series,  to  those  containing  a  larger  number  of  equiva- 
lents, we  observe  a  corresponding  change  of  properties  ; 
they  constantly  approach  nearer  the  solid  form,  and  their 
boiling  points  increase  by  a  fixed  quantity,  in  the  series  of 
acids  about  35.88°. 

II.  Ethyl,  Methyl,  etc. — Compound  radicals,  resembling 
in  their  chemical  relations,  hydrogen  and  the  metals. 

Besides  common  Ether,  C4H50,  a  great  many  other 
bodies  may  be  formed  from  alcohol,  which  possess  the 
properties  of  ether,  and  are  termed  compound  ethers,  such 
as  Hydrochloric  Ether,  C4H5C1 ;  Hydrobromic  Ether, 
C4H5Br;  Nitric  Ether,  C4H50,N05 ;  Oxalic  Ether,  C4H50, 
C203,  etc.  Now  all  these  compounds  agree  in  containing 
C4H6 ;  and  it  appears  as  though  C4H5  might  be  transferred 
from  one  compound  to  another  without  suffering  decom- 
position, in  the  same  manner  as  an  elementary  body  like 
zinc  or  copper.  To  a  body  which,  like  C4H5,  plays  the 
part  of  an  element,  we  give  a  distinct  name,  and  speak 
of  it  as  a  simple  body.  C4H5,  for  example,  is  denominated 
Ethyl,  and  represented  by  the  symbol  Ae. 

Ethyl,  like  zinc,  combines  with  the  halogen  bodies  to 
form  haloid  salts,  and  with  oxygen  and  sulphur  to  form 
oxides  and  sulphides.  The  oxides,  in  turn,  combine  with 
the  different  acids  to  form  ordinary  salts  j  thus  :— 


ETHYL.  243 

Ethyl  (symbol  Ae) C4H5 

Oxide  of  Ethyl,  Ether C4H50 

Hydrate  of  Oxide  of  Ethyl,  Alcohol C4HfiO,HO 

Chloride  of  Ethyl,  Hydrochloric  Ether C4H5Cl 

Bromide  of  Ethyl,  Hydrobromic  Ether C4H5Br 

Iodide  of  Ethyl,  Hydriodic  Ether C4H5I 

Cyanide  of  Ethyl C4H5Cy 

Nitrate  of  Oxide  of  Ethyl,  Nitric  Ether C4IJ50,N05 

Silicate  of  Oxide  of  Ethyl,  Oxalic  Ether 3(C4H50),SiOs 

The  theory  stated  above  was  proposed  by  Liebig,  long 
before  the  compound  radical  C4H5  was  ever  known  in  the 
separate  state.  Afterwards  it  was  isolated,  as  a  colorless 
liquid,  by  Dr.  Frankland,  from  Iodide  of  Ethyl,  by  expos- 
ing it  to  the  action  of  finely-divided  zinc,  at  a  temperature 
of  330°.  By  reference  to  the  above  table  of  Ethyl  com- 
pounds, it  will  be  seen  that  ether,  C4H50,  is  an  Oxide  of 
Ethyl,  and  alcohol,  C4H50,HO,  is  a  Hydrate  of  the  Oxide 
of  Ethyl,  and  that  they  may  be  expressed  by  the  formula 
AeO  and  AeO,HO. 

Ethyl  may  be  made  to  enter  into  combination  even  with 
hydrogen  and  the  metals,  and  a  long  series  of  related 
bodies  may  be  formed,  as  — 

Hydride  of  Ethyl C4H5H=AeH 

Zinc-Ethyl C4H5Zn--^AeZn 

Stannethyl C4H5Sn=AeSn 

Bismethyl (C4H5)3Bi=:Ae3Bi 

Plumbethyl (C4H5)3Pb2=Ae3Pb2 

Silibethyl (C4H5)3Sb=Ae3Sb 

Arsenethyl,  etc (C4H5)3As=rAe3As,  etc. 

And  these  compounds  may  be  made  to  combine  with  the 
halogen  bodies,  or  with  oxygen  and  the  acids,  to  form  crys- 
tallizable  salts,  as,  for  example  : — 

Stannethyl AeSn=C4H5Sn 

Oxide  of  Stannethyl AeSnO=C4H5SnO 

Chloride  of  Stannethyl AeSnCl=C4H6SnCl 

Nitrate  of  Stannethyl,  etc AeSnO,N05rrrC4H5SnO,N05,  etc. 


244  METHYL. 

Methyl. — In  like  manner,  in  all  the  Methyl-Ethers  it  will 
be  seen  that  C2H3  enters,  and  is  displaced  from  combination, 
as  a  whole.  This  compound  radical  (C2H3)  has  not  yet 
been  isolated,  but  it  has  been  confidently  assumed  to  exist. 
It  is  known  as  Methyl,  and  represented  by  the  symbol 
Me.  Wood-ether  is  regarded  as  an  Oxide,  and  wood-spirit 
as  a  Hydrated  Oxide  of  Methyl;  thus:  — 

Methyl C2H3=Me 

Oxide  of  Methyl,  Wood-Ether C2H30=MeO 

Hydrate  of  Oxide  of  Methyl,  Wood-Spirit....  C2H30,HO=MeO,HO 

Sulphate  of  Oxide  of  Methyl,  etc C2H30,S03,  etc. 

Chloride  of  Methyl C2H3C1 

Iodide  of  Methyl,  etc C2H3T,  etc. 

Hydride  of  Methyl C2H3H 

Zinc-Methyl,  etc C2H3Zn,  etc. 

Kakodyl C4H6As=:(C2H3)2As 

Kakodyl  deserves  especial  mention.  It  is  a  compound 
radical,  capable  of  entering  into  a  large  number  of  combi- 
nations, and  of  being  displaced  from  them  in  the  same 
manner  as  a  metal.  Its  most  important  compounds  are — • 

Kakodyl  (symbol  Kd) C4H6As 

Oxide  of  Kakodyl KdO 

Chloride  of  Kakodyl KdCl 

Terchloride  of  Kakodyl KdCls 

Kakodylic  Acid Kd03 

Kakodylate  of  Silver KdO,Kd03 

Tersulphide  of  Kakodyl KdS3 

Oxide  of  Kakodyl  —  KdO.  Cadet's  Fuming  Liquid, 
Alkarsin. 

Preparation. — When  equal  weights  of  Acetate  of  Po- 
tassa  and  Arsenious  acid  are  heated  together,  the  acetone 
liberated  by  the  decomposition  of  the  Acetate  of  Potassa 
reacts  upon  the  Arsenious  acid  to  form  Oxide  of  Kakodyl 
and  Carbonic  acid,  2(KO,C4H303)==2KO  +  2C02-f  2C3H30, 


KAKODYL  —  PROPYL  —  BUTYL — AMYL.  245 

and  2C3H3O  +  As03=C4H6AsO  +  2C03.  This  process  may 
be  conducted  in  an  earthen  retort  placed  in  a  furnace,  and 
having  its  beak  connected  with  a  U  shaped  tube  (Fig. 
160)  plunged  in  a  vessel  filled  with  broken 
ice.  In  this  U  tube  the  Oxide  of  Kako- 
dyl  will  collect  with  some  water  which 
covers  it. 

Properties.  —  A  colorless,  highly  refrac- 
tive liquid;  density  1.462,  and  boiling  point 
302°.  It  is  highly  poisonous,  and  attacks 
the  eyes  and  lining  membrane  of  the  nose. 
It  takes  fire  in  air,  producing  water,  car- 
bonic and  arsenious  acids.  When  treated  with  corrosive 
sublimate  and  hydrochloric  acid  it  yields  an  extremely 
poisonous  liquid,  Chloride  of  Kakodyl. 

Kakodyl— Kd. 

Preparation. — Digested  with  zinc  the  Chloride  of  Kak- 
odyl suffers  decomposition,  with  the  formation  of  Chloride 
of  Zinc  and  Kakodyl  itself,  KdCl+Zn=ZnCl  +  Kd. 

Properties.  —  A  colorless,  transparent  liquid,  of  great 
inflammability.  It  boils  at  338°,  and  at  21°  crystallizes 
in  transparent  square  prisms.  Combines  directly  with 
oxygen,  sulphur,  chlorine,  etc.  Its  teroxide,  alkargen, 
Kd03,  is  a  very  stable  acid,  capable  of  uniting  with  me- 
tallic oxides  to  form  cryztallizable  salts.  In  union  with 
cyanogen,  as  KdCy,  it  is  said  to  form  the  most  violent 
of  all  poisons. 

Propyl,  C6H7;  Butyl,  C8H9;  Amyl,  CIOHn;  etc. 

These  are  the  compound  radicals  of  the  long  series  of 
alcohols  and  ethers  homologous  with  wood-spirit  and 
wood-ether.  As  oxides  they  form  ethers,  and  as  hy- 
drated  oxides  alcohols.  (See  page  243).  Their  alcohols, 
when  oxidized,  yield  homologous  acids. 
21* 


246  BENZOYL. 

Benzoyl,  C14H502;  Cinnamyl,  C18H702;  and  Salicyl,  C14H504. 

1.  Benzoyl— C14H502.    Symbol,  Bz. 

Benzoyl  is  a  compound  radical,  capable  of  isolation, 
which  can  be  made  to  combine  directly  with  chlorine,  hy- 
drogen, oxygen,  etc.,  and  to  fulfil  the  part  of  a  metal.  Its 
most  important  compounds  are — 

Hydride  of  Benzoyl,  Bitter-Almond  Oil C14H502H 

Hydrated  Oxide  of  Benzoyl,  Benzole  Acid C]4H502HO,HO 

Chloride  of  Benzoyl C14H502C1 

Benzoic  Alcohol C14H70,HO 

Hydride  of  Benzoyl — BzH.  Bitter- Almond  Oil.  This 
oil  is  obtained  by  distilling  bitter  almonds,  after  they  have 
been  crushed  and  the  fixed  oil  expressed,  with  water. 
The  water  is  essential  to  the  formation  of  the  oil,  inas- 
much as  it  acts  upon  a  crystallizable  principle,  called 
Amygdalin,  which  exists  in  the  seed,  and,  aided  by  nitro- 
genous substances,  likewise  contained  in  the  pulp,  forms 
from  it  bitter-almond  oil. 

Properties.  —  It  is  a  thin  liquid,  of  agreeable  odor  and 
high  refractive  power;  its  density  is  1.043,  and  boiling 
point  356°.  Exposed  to  the  air,  it  absorbs  oxygen  with 
rapidity,  and  is  converted  into  Benzoic  acid. 

Benzole  Acid — BzO,HO.  Oxide  of  Benzoyl.  It  may  be 
obtained  in  large  quantities  by  heating  some  of  the  bal- 
sams, especially  gum  benzoin. 

Properties. — It  enters  readily  into  combination  with  the 
alkalies  and  metallic  oxides  to  form  soluble  crystallizable 
salts.  By  prolonged  heating  with  fuming  nitric  acid  it 
forms  two  new  acids,  Nitrobenzoic,  C14(H4N04)03,HO  and 
Binitrobenzoic,  C14(H3(N04)2)03,HO ;  in  the  former  of 
which  one  atom,  and  in  the  latter  two  atoms  of  hydrogen 
are  replaced  by  Hyponitric  acid.  These  substitutions  are 


BENZOL  —  ANILINE  —  CINNAMYL  —  SALICYL.          24  7 

of  constant  occurrence,  and  should  be  studied  in  order  to 
understand  important  operations  in  manufacturing  chem- 
istry. 

Benzol—  C,2H6. 

Preparation.  —  It  may  be  formed  by  decomposing  Ben- 
zoic  acid  by  Hydrate  of  Lime;  thus,  C,4H604-f  2CaO, 
HO  =  C12H6+2CaO,C02+HO,  or  by  distilling  bituminous 
coal  (see  p.  233).  Benzol  has  recently  become  of  great 
importance,  as  the  source  of  Aniline,  by  the  following 
series  of  transformations  :  Benzol  is  first  converted  into 
Nitrobenzol,  C12H5N04,  by  heating  with  fuming  nitric 
acid,  and  then  the  nitrobenzol  changed  to  aniline  by  dis- 
tillation with  acetic  acid  and  iron  filings,  C,  H5N04-f- 


Aniline,  Ci2H7,  is  an  oily,  colorless  liquid,  of  density 
1.028,  and  boiling  point  360°.  It  enters  into  combination 
with  acids  and  forms  many  beautiful  crystallizable  salts. 
That  formed  with  sulphuric  acid,  the  Sulphate  of  Aniline, 
gives  with  Bichromate  of  Potash  the  exquisite  mauve 
color  patented  by  Mr.  Perkins,  which  was  the  first  formed 
of  the  many  commercial  aniline  dyes. 

Cinnamyl—  C18H702,Ci. 

Like  benzoyl,  this  radical,  when  combined  with  hydro- 
gen, yields  an  oil,  the  Oil  of  Cinnamon,  CI8H702,H.  Its 
hydrated  oxide  forms  an  analogous  acid,  Oinnamic  acid, 
C18H7020,HO.  It  unites  with  chlorine  to  form  a  Chloride 
of  Cinnamyl,  C18H702C1,  and  forms  Cinnamylic  Alcohol, 
CJ8H90,HO,  corresponding  to  Benzoic  Alcohol,  C14H70, 
HO. 

Salicyl—  CI4H504- 

As  a  Hydride,  C14H504,H,  Salicyl  forms  an  oil,  which 
has  been  found  to  be  identical  with  that  distilled  from  the 
flowers  of  meadow-sweet.  This  artificial  oil  has  been  ob- 
tained from  Salicin,  C26H1804,  the  bitter  principle  of  poplar 
and  willow  bark. 


248 


OXALIC    AND    TARTARIC    ACIDS. 


IE.   VEGETABLE  ACIDS. 

Under  this  section  are  included  those  acids  which  are 
not  formed  artificially  by  oxidation  of  the  alcohols  or  by 
other  means,  but  exist  ready  formed  in  plants.  They  are 
sometimes  met  with  in  the  free  state,  but  generally  in 
combination  with  bases.  The  most  important  are — 


Oxalic  Acid C406,2HO 

Tartaric  Acid C8H4010,2HO 

Citric  Acid C12H5On,3HO 


Malic  Acid C8H408,2IIO 

Tannic  Acid C^H^ 

Gallic  Acid C7H03,2HO 


Oxalic  Acid— C406,2HO. 

It  is  found  in  combination  with  potassa  or  lime  in  many 
plants,  and  particularly  in  various  kinds  of  sorrel  (Oxalis^). 

Preparation. — It  may  be  formed  by  digesting  any  sac- 
charine or  amylaceous  matter  with  moderately  strong 
Nitric  acid.  Thus,  1  part  of  Sugar,  5  parts  of  Nitric 
acid  of  sp.  gr.  1.42,  and  10  parts  of  Water,  when  heated 
together,  yield  on  cooling  colorless  crystals  of  Oxalic  acid. 
The  nitric  acid  gives  up  its  oxygen  to  the  sugar,  and  we 
have  C24H18018+360=6(C406)  +  18HO. 

Properties. — Extremely  sour,  very  soluble  in  water, 
highly  poisonous,  and  capable  of  combining  with  the  alka- 
lies, earths,  and  metals  to  form  crystalline  salts.  It  is 
bibasic,  and  forms  two  series  of  salts,  one  containing  2 
equivalents  of  the  basic  body,  the  other  1  equivalent  along 
with  one  atom  of  water.  Will  remove  stains  made  by 
common  ink.  Sold  for  this  purpose  under  the  name  of 
Salts  of  Lemon. 

Tartaric  Acid— C8H4010,2HO. 

Found  combined  with  potassa  in  many  fruits,  especially 
grapes,  tamarinds,  and  pineapples. 

Preparation. — When  the  juices  of  these  fruits  are  fer- 
mented, as  in  the  manufacture  of  wine,  the  Acid  Tartrate 
of  Potassa  is  thrown  down,  and  forms  a  coating  on  the 


EOCHELLE    SALT  —  CITRIC    ACID.  249 

sides  and  bottoms  of  the  cask,  called  Argol  or  Tartar. 
When  argol  is  repeatedly  washed,  filtered  with  animal 
charcoal,  and  crystallized,  it  is  converted  into  Cream  of 
Tartar,  or  nearly  pure  acid  Tartrate  of  Potassa,  KO,HO, 
C8H4010.  From  this  substance,  by  neutralization  with 
lime  and  subsequent  removal  of  the  bases  by  sulphuric 
acid,  Tartaric  acid  may  be  obtained. 

Properties. — Large,  white,  colorless,  transparent  crys- 
tals, readily  soluble  in  water.  Strongly  acid  to  the  taste, 
and  quickly  reddens  litmus.  It  is  bibasic,  and,  like  all  the 
other  vegetable  acids,  containing  2  equivalents  of  basic 
water,  forms  two  series  of  salts,  one  containing  2  and  the 
other  1  equivalent  of  the  base. 

Use. — Tartaric  acid  is  largely  employed  in  calico  print- 
ing, to  liberate  from  bleaching  powder  the  chlorine  neces- 
sary to  bleach  part  of  the  colored  print,  in  order  to  form  a 
pattern. 

Its  most  important  salts  are — 

Rochelle  Salt— KO,NaO,C8H4010+8HO.  Tartrate  of 
Potassa  and  Soda.  It  is  obtained,  by  neutralizing 
Cream  of  Tartar  with  Carbonate  of  Soda,  in  very  soluble 
crystals.  It  is  used  as  a  purgative. 

Tartar-Emetic— KO,Sb03,C8H40104-4HO.  Tartrate  of 
Potassa  and  Antimony. 

Preparation.  —  Equal  parts  of  Cream  of  Tartar  and 
Oxide  of  Antimony  are  boiled  with  6  parts  of  water. 

Use. — Largely  employed  in  medicine. 

Effervescing  'mixtures  are  composed  either  of  Tartaric 
acid  and  Bicarbonate  of  Soda  (Soda  powders),  or  Tartaric 
acid  and  Bicarbonate  of  Soda  with  Rochelle  Salt  (Seidlitz 
powders). 

Citric  Acid— C12H5On,3HO. 

Exists  in  the  juices  of  the  lemon  (citron)  and,  to  a 
smaller  extent,  of  orange,  currant,  gooseberry,  etc. 

Preparation. — A  Citrate  of  Lime  is  formed,  in  the  first 


250  MALIC    AND    TANNIC    ACIDS. 

place,  by  neutralizing  lemon-juice  with  lime,  and  after- 
wards decomposed  by  sulphuric  acid. 

Properties.  —  On  evaporation,  the  citric  acid  thus  set 
free,  separates  in  colorless  crystals  of  great  solubility, 
strongly  acid  character,  and  agreeable  taste.  It  is,  as  its 
formula  indicates,  tribasic.  By  heating  with  Nitric  acid, 
it  is  converted  into  Oxalic  acid;  with  Caustic  potassa, 
into  Oxalic  and  Acetic  acids. 

Uses.  —  In  calico  printing ;  in  imparting  an  agreeable 
flavor  to  cookery ;  in  making  effervescent  drinks,  and  as  a 
Citrate  of  Magnesia,  for  a  pleasant-tasting  purgative. 

Tests.  —  A  white  precipitate  with  baryta,  strontia,  and 
lead. 

Malic  Acid— C8H408,2HO. 

Sources.  —  It  is  found  in  large  quantities  in  unripe 
fruits,  such  as  the  apple  (Malum),  pear,  plum,  etc. ;  also 
in  vegetables,  such  as  the  rhubarb,  or  pie-plant. 

Properties.  —  Forms  soluble  crystals,  which  melt  at 
181°.  By  heating,  it  is  converted  into  two  other  acids, 
the  maleic  and  paramaleic  or  fumaric  acids,  both  of 
which  have  the  formula  C8H206,2HO,  and  are  therefore 
isomeric,  that  is,  they  consist  of  the  same  elements  in  the 
same  proportion. 

Tannic  Acid— C54H19031,3HO.    Tannin. 

Sources. — Found  in  the  bark  and  leaves  of  the  oak, 
chestnut,  hemlock,  and  many  other  trees.  Forms  a  large 
portion  of  nut  galls,  which  are  excrescences  upon  oak 
leaves. 

Preparation.  —  It  maybe  obtained  by  steeping  pow- 
dered nutgalls  in  Sulphuric  ether. 

Properties. — It  hardens  as  a  yellow  substance,  devoid 
of  crystalline  structure,  which  is  soluble  in  water,  and  of 
peculiar,  astringent  taste ;  it  reddens  litmus,  and  forms 
salts  with  bases ;  but  its  acid  characters  are  feeble. 

Uses.  — With  Sesquioxide  of  iron,  it  forms  a  Tannate, 


ORGANIC    BASES.  251 

which,  when  mixed  with  gum  to  hold  the  insoluble  Tan- 
nate  of  iron  in  suspension,  constitutes  common  writing 
ink.  Besides  its  employment  in  ink  making,  it  is  used  in 
enormous  quantities  in  tanning.  After  the  hair  has  been 
removed  from  hides,  they  are  soaked  in  vats  containing 
oak  and  hemlock  bark.  The  Tannic  acid  so  obtained 
unites  with  the  Gelatine  contained  in  the  hides,  and 
forms  an  insoluble  compound  with  it,  which  is  the  basis 
of  leather. 

Gallic  Acid— C7H03,2HO. 

Preparation.  —  It  is  found,  along  with  Tannic  acid,  in 
vegetable  bodies,  and  produced  whenever  this  acid  is 
exposed  to  the  atmosphere,  or  boiled  with  Sulphuric 
acid. 

Properties. — A  crystalline  body,  insoluble  in  cold,  but 
very  soluble  in  hot  water.  It  is  converted  by  heating 
into  Pyrogallic  and  Metagallic  acids:  thus,  C7H305=CO2 
4-C6H808  (Pyrogallic  acid),  and  C6H303=  HO  +  C6H202 
(Metagallic  acid). 

Uses. — A  Tanno-gallate  of  Iron  mixed  with  Sulphate  of 
Indigo  forms  blue  ink.  Gallic  and  Pyrogallic  acids  are 
also  employed  to  develop  photographs.  * 


IV.  ORGANIC  BASES. 
I.  ORGANIC  ALKALIES,  OR  ALKALOIDS. 

Some  are  found  ready  formed,  others  are  obtained  from 
plants  by  destructive  distillation.  They  are  always  found 
in  combination  with  peculiar  acids,  forming  true  salts. 
All  contain  nitrogen.  In  water,  they  dissolve  sparingly, 
readily  in  alcohol,  and  on  cooling,  form  beautiful  crys- 
tals. A  few,  however,  are  oily,  volatile  liquids.  They 
have  a  very  bitter  taste,  and  are  highly  poisonous :  the 
proper  antidotes  are  animal  charcoal  and  tannin.  The 
most  important  are: — 


252  MORPHIA  —  CINCHONIA. 


Morphia 

Narcotina  ......................  C48H25NO)4. 

Cinchonia  ......................  C40H24N202. 

Quinia  ...........................  C^H^N^. 

Strychnia  .......................  C42H22N204. 

Brucia  ...........................  C^HggNgOg. 

Veratria  .......................  C^H^O^. 

Caffeine  ........................  C16H16N404. 

Conia  .............................  Ci6H17N02. 


Morphia— C34H19N06+  2HO  (crystallized). 

Sources. — Exists  along  with  narcotina,  codeia,  thebaia, 
papaverina,  opianine,  resin,  oil,  gum,  etc.,  in  opium,  or 
dried  poppy-juice.  They  are  found  in  combination  with  a 
peculiar  acid,  the  meconic  (from  mecone,  a  poppy).  In 
100  parts  of  opium,  there  are  7  per  cent,  of  Meconic  acid, 
10  of  Morphia,  and  7  of  Narcotina. 

Preparation. —  It  is  separated 'by  digesting  opium  for 
several  days  in  alcohol,  and  precipitating  by  ammonia. 
The  morphia  thus  obtained,  is  purified  by  solution  in  boil- 
ing alcohol,  from  which  it  deposits  on  cooling. 

Properties.  —  It  crystallizes  in  brilliant  rectangular 
prisms,  which  contain  2  equivalents  of  water  of  crystal- 
lization. At  a  gentle  heat  the  water  is  driven  off,  and 
the  morphia  solidifies  into  a  resinous  mass.  It  requires 
1000  parts  of  cold,  or  400  of  hot  water  for  solution ;  of  al- 
cohol, only  30  parts ;  dissolves  also  in  acids,  fixed  alka- 
lies, and  alkaline  earths. 

Use. — In  doses  of  J  to  J  of  a  grain  employed  in  medi- 
icine ;  so  likewise  the  Sulphate,  Muriate,  and  Acetate  of 
Morphia. 

Tests.  —  Colored  green  by  mixture  of  Nitric  and  Sul- 
phuric acids ;  blue  by  neutral  solution  of  Perchloride  of 
Iron. 

Cinchonia,  C40H24N202,  and  Quinia,  C4oH24N204. 

Source. — They  are  found  associated  together  in  the  bark 


QUINIA   AND    ISOMERIC    BODIES.  253 

of  the  Cinchona  tree,  which  grows  extensively  in  South 
America,  and  is  known  in  commerce  as  Peruvian  bark. 
The  former  is  found  most  abundantly  in  the  pale  or  Loxa 
bark ;  the  latter  in  the  yellow  or  red,  the  Calisaya  bark. 
They  are  combined  with  Kinic  acid. 

Preparation.  —  The  powdered  bark  is  dissolved  in  al- 
cohol, the  alkali  precipitated  by  lime  or  ammonia,  then 
boiled  in  alcohol  and  converted  into  Sulphate.  From 
solution,  the  Sulphate  of  Quinia,  being  less  soluble,  crys- 
tallizes out  first. 

Properties.  —  Cinchonia  crystallizes  in  very  beautiful 
transparent  prisms.  It  has  strongly  basic  properties,  and 
forms  many  crystallizable  salts.  It  turns  the  plane  of 
polarized  rays  to  the  right. 

Quinia  crystallizes  less  distinctly,  but  is  more  soluble 
than  Cinchonia.  It  has  an  intensely  bitter  taste  ;  rotates 
the  plane  of  polarization  to  the  left.  Its  most  important 
salts  are  the  Muriate  and 

Sulphate  of  Quinia,  C40H24N204,HO,S03+'TH().  This 
is  the  neutral  Sulphate,  but  there  is  likewise  an  acid  salt. 
It  forms  with  iodine  a  beautiful  crystalline  body,  which 
has  the  same  absorbent  power  upon  light  as  tourmaline, 
and  may  be  used  as  a  substitute  for  it  in  the  polariscope. 

Uses. — Quinia  is  very  largely  employed  in  medicine  on 
account  of  its  febrifuge  and  antiperiodic  powers  ;  Sulphate 
of  Quinia  to  display  the  phenomena  of  fluorescence. 

Isomeric  Bodies. — If  these  Quinia  salts  be  exposed  to 
sun-light,  or  treated  with  excess  of  acid,  they  pass  into  a 
resinous  condition,  and  constitute  Quinoidine.  This  is  in 
reality  a  mixture  of  two  alkaloids,  one  of  which  has  the 
same  properties  or  is  isomeric  with  Quinia,  Quinidine, 
the  other  isomoric  with  Cinchona,  Ginchonidine ;  and 
when  these  two  substances  are  exposed  to  a  temperature 
of  250°  they  are  changed  into  two  other  isomeric  bodies, 
Quinicine  and  Cinchonicine.  The  most  remarkable  dif- 
22 


254  STRYCHNIA  —  BRUCIA  —  VERATRIA. 

ference  between  them  all  is  in  their  action  upon  the  plane 
of  polarization ;  for 

Quinia  produces  a  powerful  rotation  to  the  left. 
Quinidine        "  "  "  '       right. 

Quinicine        "        feeble  "  '       right. 

Cinchona        "        powerful        "  <       right. 

Cinchonidine  "  "  "  '       left. 

Cinchonicine  "        feeble  "  '       right. 

Strychnia,  C44H22N204,  and  Brucia,  C46H26N2O8. 

Source. — They  are  found  associated  together  in  the  fruit 
and  bark  of  Nux  Vomica  and  in  St.  Ignatius  Bean.  In 
the  former  they  are  combined  with  lactic  acid. 

Preparation.  —  They  are  precipitated  by  excess  of  hy- 
drate of  lime,  filtered  from  solution  in  boiling  alcohol,  and 
afterwards  separated  by  cold  alcohol.  Strychnia  crystal- 
lizes out  first. 

Properties. — Small,  transparent,  colorless,  very  brilliant 
octahedrons;  soluble  in  6661  parts  cold  and  2000  parts 
boiling  water;  very  slightly  soluble  in  cold  alcohol  or  ether. 
Yery  bitter  and  fearfully  poisonous. 

Bmcia  is  distinguished  from  Strychnia  by  its  ready  sol- 
ubility in  alcohol,  and  by  giving,  when  its  salts  are  mixed 
with  Tartaric  acid,  no  precipitate  with  Bicarbonate  of 
Soda. 

Tests. — Moistened  with  Sulphuric  acid,  Strychnia  gives 
with  Bichromate  of  Potassa  a  beautiful  violet  tint,  passing 
into  pale  rose.  Brucia  and  its  salts  afford  a  bright  scarlet 
color,  gradually  passing  into  yellow  with  Nitric  acid ;  on 
addition  of  Protochloride  of  Tin  a  fine  violet. 

Veratria— C64H52N2016. 

Source. — Occurs  principally  in  combination  with  Gallic 
acid  in  several  varieties  of  Veratrum. 

Properties.  —  An  acrid,  fearful  poison,  producing,  on 
contact  with  the  nasal  membrane,  dangerous  fits  of 
sneezing. 


ETHYL   AMMONIAS.  255 

Use.  —  Sedative  in  neuralgia,  when  applied  as  an  ex- 
ternal ointment. 

Test. — Strikes  with  Nitric  acid  a  red  color  slowly  chang- 
ing to  yellow. 

Caffeine,  C16H10N404,  or  Theine. 

Remarkable  as  being  found  in  the  grains  of  coffee  and 
in  the  leaves  of  tea,  Paullinia  sorbilis,  and  Ilex  Para- 
guayensis,  from  which  the  universal  beverages  are  ob- 
tained. 

Conia,  C16H15N,  and  Mcotina,  C10H7N. 

They  differ  from  all  other  alkaloids  in  forming  oily, 
volatile  liquids.  The  first  is  the  poisonous  principle  of 
hemlock,  the  second  of  tobacco. 


II,  ARTIFICIAL  ORGANIC  BASES,  OR  ARTIFICIAL 
ALKALOIDS. 

The  best  method  of  studying  the  production  and  con- 
stitution of  these  bodies  is  by  comparing  them  with  am- 
monia; for,  like  ammonia,  they  all  contain  nitrogen,  have 
alkaline  properties,  and  are  capable  of  combining  with 
acids  to  form  crystallizable  salts.  They  may  be  consid- 
ered, indeed,  as  ammonia,  in  which  one  or  more  equiva- 
lents of  hydrogen  are  replaced  by  the  same  number  of 
equivalents  of  the  compound  radicals,  ethyl,  methyl,  phe- 
nyl,  etc.  ;  thus 

H  C4H5  fC4H5  fCJT, 

H 


H  H  4H5 

Ammonia.    Ethyl-ammonia,    Biethyl-ammonia,  Triethyl-ammonia, 
or  Ethylamine.     or  Biethylamine.     or  Triethylamine. 

The  Ethyl  Ammonias. 

1.  Ethylamine—  N(C4H5)H2=G4H7K 

Preparation.  —  Formed  by  heating  strong  ammonia 
with  iodide  of  ethyl  in  hermetically  sealed  tubes  :  thus, 
C4H5I+NH3  =  N(C4H5)H3I,  and  distilling  the  product 


256  BIETHYLAMINE — TRIETHYLAMINE. 

with  caustic  potash,  N(C4H5)H3I  +  KO  =  N(C4H5)H2+ 
HO+KL 

Properties. — A  thin  mobile  fluid,  strongly  alkaline,  and 
combining,  like  Ammonia,  to  form  many  crystallizable 
salts.  It  forms  a  Hydrochlorate  of  ethylamine,  with  the 
formation  of  white  clouds,  similar  to  those  arising  from 
the  combination  of  Hydrochloric  acid  and  Ammonia. 
Like  Ammonia,  it  precipitates  the  Salts  of  Alumina, 
Magnesia,  Iron,  Manganese,  Bismuth,  Chromium,  Tin, 
Lead,  and  Mercury. 

Biethylamine— N(C4H5)2H==C8HUN,  and 

Triethylamine— N(C4H5)3==  C  ]2H15K 

Preparation.  —  They  are  produced  by  reactions  analo- 
gous to  those  between  ammonia  and  iodide  of  ethyl ; 
ethylamine,  or  biethylamine  taking  the  place  of  the 
former:  thus,  N(C4H5)H2+C4H5Br=N(C4H5)2H2Br;  and 
jST(C4H5)2H2Br-fKO=N(C4H5)2H+HO+KBr. 

Properties. — With  the  increase  of  equivalents  of  the 
elements  composing  them,  there  is  a  corresponding  rise  of 
boiling  point ;  ethylamine  boiling  64.4°,  biethylamine  at 
133°,  triethylamine  at  195.8°.  Their  alkaline  properties 
correspondingly  diminish,  though  all  form  beautiful  salts. 
As  we  have 

fH]  f0^6] 

N    H    0,HO  so  N    %Mo,HO. 

LHj  [C4H5J 

Hydrated  oxide  of  ammonium.  Hydrated  oxide  of  tetrethyl- 

ammonium. 

Hydrated  Oxide  of  Tetrethyl-ammonium  —  N(C4H5)4== 

C16H20N. 

Properties.  —  It  is  powerfully  alkaline,  and  closely  re- 
sembles potassa,  or  soda,  combining  like  them  with  fatty 
acids  to  form  true  soaps,  and  with  metallic  salts  acting 
precisely  like  potassa.  In  its  excessively  bitter  taste, 
resembles  the  alkaloids  proper. 


METHYL   AND   AMYL   AMMONIAS.  25T 

The  Methyl  Ammonias. 
rC2H3  rc2H3  rc2H3  fC2H3] 

N       H  N     CH3  N    C,Ha  N!  C2H3  a 

I   a.  {   a.  I^2ti3  L2H3  | 


Methylamine.  Bimethylamine.  Trimethylamine.  Hydrated  oxide  of 
=C2H5N.  =C4H7N.  =CeH9N.  tetre  methyl-am- 

monium. 

Preparation.  —  As  hydrated  cyanic  acid  (C2NO,HO), 
when  boiled  with  caustic  potassa,  is  decomposed  into  2 
Eq.  of  Carbonic  acid  and  1  Eq.  of  Ammonia,  so  is  Cyanate 
of  Ethyl,  or  Methyl,  into  2  Eq.  of  Carbonic  acid  and  1 
Eq.  of  Ethylamine,  or  Methylamine:  thus,  C2NO,HO  + 
2(KO,HO)=2(KO,C02)  +  NH3:  and  C2NO,(C4H5)0  or 
C2NO,(C2H3)0  +  2(KO,HO)  =2(KO,C02)  +  N(C4H5)H2; 
or  N(C2H3)H2. 

Properties.  —  The  first  three  are  gases  closely  resem- 
bling ammonia.  Methylamine  smells  slightly  fishy,  Tri- 
methylamine  strongly  so;  the  latter  is  found  in  consider- 
able quantity  in  the  roe  of  herring.  The  density  of  Am- 
monia is  0.589,  of  Methylamine  1.08  ;  the  former  is  solu- 
ble in  T^Q  its  bulk  of  water,  the  latter  in  J^QQ,  and,  con- 
sequently, is  the  most  soluble  of  all  gases. 

The  Amyl  Ammonias. 

c10Hn 


fC10Hu  rc10Hn 

N   H      N  C  Hll 

(.    a.  (     H 


cOHO 


Amylamine.     Biamylamine.     Triamylamine.  Hydrated  oxide  of  Te- 
=C10Hi3N.         ^zrCgoH^N  =nC3oH33N.         tramyl-ammonium. 


Properties.  —  A  series  of  strongly  alkaline  bodies,  whose 
basic  power  diminishes  and  boiling  point  increases  as  the 
series  ascends;  thus,  Amylamine  boils  at  199.4°,  Biamyl- 
amine at  338°,  Triamylamine  at  494.6°. 
22* 


258  ARTIFICIAL    ORGANIC    BASES. 

Phenyl  Ammonia. 

Aniline  or  Phenylamine — N(C12H5)H2=C12H7K 
Preparation.  —  When  Salicylic  acid,  C14H4042HO  (p. 
247),  is  strongly  heated  it  is  decomposed  into  Carbonic 
acid  and  Carbolic  acid  or  Phenol,  C12H602.  The  same 
body  is  found  in  the  acid  portion  of  coal-tar  (p.  233).  It 
so  closely  resembles  the  alcohols  that  it  is  assumed  to  be 
in  composition  a  hydrated  oxide  of  a  compound  radical, 
Phenyl,  C12H5  (Sym.  Pyl) ;  and  the  body  formed  by  heat- 
ing Phenol  with  Ammonia,  Aniline,  C12H7lSr  (p.  259),  has 
in  like  manner  been  regarded  as  a  phenyl-ammonia ;  thus, 
PylO,HO+NH3=2HO+ N(Pyl)H2,  or  C12H7N. 

Substitution- Products  of  Aniline. — Besides  the  substi- 
tution of  compound  radicals  for  the  hydrogen  in  Ammonia, 
the  hydrogen  of  the  new  artificial  bases  may  in  like 
manner  be  replaced  by  Chlorine,  Bromine,  Hyponitric 
acid,  etc. ;  thus — 


Aniline N(C,2H5)H2 

Chloraniline N(C12H4C1)H2 

Bromanilme N(C,2H4Br)H2 

Bibromaniline N(C]2H3Br2)H2 

Nitraniline N(C12H4N04)H2 


III,  ARTIFICIAL  ALKALOIDS  HOMOLOGOUS  WITH 
ANILINE. 

As  we  had  a  hydrocarbon  Benzol,  Ci2H6  (p.  246),  de- 
rived from  the  radical  Benzoyl,  C14H502,  -so  likewise  from 
the  homologous  radicals,  Toluyl,  Ci6H702;  Xylil,  C18H902; 
Cumyl,  C2oHn02,  and  Cymyl,  C22H1302,  result  the  hydro- 
carbons homologous  with  Benzol,  C12H6,  namely,  Toluol, 
C14H8;  Xylol,  Ci6H10;  Cumol,  C18H12,  and  Cymol,  C20HI4. 

And  as  Benzol  was  converted  into  Nitrobenzol  by  fum- 


ARTIFICIAL    ALKALOIDS.  259 

ing  Nitric  acid,  so  may  its  homologues  be  changed  to 
homologous  nitro-substitution  hydrocarbons  ;  and  the  ac- 
tion of  Sulphuretted  Hydrogen  upon  these  last  is  the  same 
as  its  action  on  Nitrobenzol,  C12H5N04,  viz.,  C12H5N04+ 
6HS  =  C12H7N  +  4HO  +  6S.  We  have  formed  in  this 
manner:  — 

Benzol,  C12H6H  Nitrobenzol,  C12H5N04  Aniline,      N(C12H5)H2 

Toluol,  C14H7H  Nitrotoluol,   C14H7N04  Toluidine,  N(G14H7)H2 

Xylol,  C16H9H  Nitroxylol,    C,6H9N04  Xylidine,    N(C,6H9)H2 

Cumol,  CI8HnH  Nitrocumol,  C,8HUN04  Cumidine,  N(Ci8Hn)H2 

Cymol,  C2oH13H  Nitrocymol,  C^H^NC^  Cymidine,  N(C20H,3)H2 


Properties.  —  They  resemble,  in  their  derivation,  forma- 
tion, and  properties,  Aniline.  They  form  beautifully  crys- 
talline salts. 


IV.  ARTIFICIAL  ALKALOIDS  CONTAINING  SEVE- 
RAL COMPOUND  RADICALS, 

The  Hydrogen  in  Ammonia  may  not  only  be  replaced 
by  a  single  compound  radical,  but  also  by  several  different 
ones.  In  this  manner  Ethyl,  Methyl,  etc,  may  occur  in 
the  same  artificial  base  :  — 

Ammonia NH4        I  Ethylaniline NPylAeH 

Aniline NPylH2  I  Biethylaniline  NPylAe2H 

So  from 

Hydrated  Oxide  of  Ammonium NH40,HO 

«  "         Triethyl-phenyl-ammonium  N(PylAe3)0,HO 

"  "         Triethyl-amyl-ammonium...  N(AylAe3)0,HO 

"  "         Methyl-bietkyl-amyl-animo- 

nium N(AylAe2Me)0,HO 

"  "          Methyl-ethyl-amyl-phenyl- 

ammonium N(PylAylAeMe)0,HO 

Properties. — All  these  Ammonium  bases  are  powerfully 
alkaline,  and  resemble  strikingly  the  Hydrated  Oxide  of 
Tetrethyl-anunonium,  p.  256. 


260  OILS. 

V,  OILS. 

The  term  Oil  is  applied  to  a  great  variety  of  bodies, 
which  agree  in  the  general  properties  of  inflammability, 
sparing  solubility  in  water,  and  ready  solubility  in  alcohol 
or  ether.  It  is  usual  to  associate  greasiness  with  oils,  but 
this  idea  requires  limitation.  Fixed  oils  (see  below)  are 
greasy,  volatile  oils  are  not ;  they  are  harsh  to  the  touch. 
Mineral  oils  are  intermediate.  And  when  a  cork  is  twisted 
into  a  bottle  containing  a  fixed  oil  it  makes  no  noise ;  in 
other  oils  it  squeaks. 

Classification  of  Oils.  —  They  are  most  conveniently 
divided  into  three  classes,  according  to  their  origin,  viz., 
vegetable,  animal,  and  mineral.  The  latter  have  been 
treated,  under  the  changes  produced  in  lignine  by  decay 
and  distillation  (p.  233)  ;  the  former  agree  so  closely  in  all 
their  properties,  that  they  are  best  considered  together. 

Classification  of  Vegetable  and  Animal  Oils.  — Vegeta- 
ble and  animal  oils  are  of  two  kinds,  (a)  fixed  and  (6) 
volatile;  so  named  from  producing,  the  former  a  perma- 
nent, the  latter  a  transient,  stain  when  dropped  on  paper. 
Both  classes  absorb  oxygen  ;  some  slowly,  others  so  rap- 
idly as  to  inflame  spontaneously.  In  consequence  of  this 
difference,  oils  are  farther  divided  into  drying  —  those 
which,  like  linseed,  poppy-seed,  and  walnut  oils,  become 
hard  on  exposure  to  air — and  non-drying — those  rancidify- 
ing  only,  as  olive,  palm,  and  most  animal  oils.  In  virtue 
of  their  siccative  properties,  drying'  oils  are  largely  em- 
ployed in  painting. 

Sources  of  Oils.  —  Oils  are  found  in  the  stems,  leaves, 
and  fruits  of  plants,  but  abound  chiefly  in  the  seed.  In 
animals  they  are  stored  up  everywhere,  but  principally 
just  beneath  the  cuticle  j  also  in  the  omentuni  and  around 
the  kidneys. 

Properties. — They  are  generally  lighter  than  water,  the 


FIXED   OILS.  261 

fixed  oils  varying  in  density  from  0.91  to  0.94,  and  the 
volatile  from  0.846  to  1.097.  They  vary  likewise  in  their 
melting  points,  some  being  solid  at  ordinary  temperatures, 
others  liquid.  In  general,  the  greater  the  proportion  of 
carbon  they  contain  the  lower  the  melting  point. 

(a)  Fixed  Oils,  also  called  Fats. 

Preparation. — When  found  in  vegetables,  they  are  ob- 
tained by  submitting  the  crushed  seeds  or  other  vegetable 
structure  to  pressure,  or  pressure  and  heat  combined. 
From  animals  they  are  obtained  by  breaking  up  the  adi- 
pose membrane.  This  may  be  effected  sometimes  by  the 
decay  of  the  cellular  structure,  in  other  cases  by  liquefac- 
tion and  expansion  of  the  fat,  which  runs  out  or  collects, 
on  boiling,  at  the  surface  of  the  water. 

Properties. — They  are  generally  colorless,  or  of  a  slight 
yellow  tinge,  bleaching  on  exposure  to  light;  of  faint  odor 
and  slight  taste.  In  some  cases,  however,  peculiar  odors 
are  imparted  by  volatile  fatty  acids,  as  to  butter  by  butyric 
acid,  to  goat's  fat  by  hircic  acid,  etc.  They  are  all  insol- 
uble in  water,  and,  with  the  exception  of  castor-oil,  but 
slightly  soluble  in  alcohol.  In  ether,  the  essential  oils, 
and  benzol  they  dissolve  freely.  They  can  be  heated  to 
nearly  500°  without  much  change,  but  beyond  that  point 
they  are  decomposed,  and  cannot  therefore  be  distilled. 
When  heated  to  about  500°,  they  change  color  and  evolve 
offensive  odors ;  at  a  little  above  600°,  they  are  decom- 
posed and  distil,  with  the  formation  of  solid  and  liquid 
hydrocarbons,  water,  fatty  acids,  and  Acrolein,  C6H40^ — 
an  excessively  volatile,  irritating  liquid. 


262  SAPONIFICATION. 

Composition. — They  all  consist  of  carbon,  hydrogen,  and 
oxygen;  for  example,  in  100  parts  of  the  following  oils 
there  are 

Carbon.  Hydrogen.  Oxygen. 

Olive 77.21  13.36                  9.43 

Almond 77.40  11.48  10.82 

Linseed 76.01  11.35  12.62 

Castor 14.17  11.03  14.78 

Whale 76.13  12.40  11.50 

Spermaceti 78.91  10.97  10.12 

Hog's  Lard 79.09  11.14                  9.75 

Suet 78.99  11.70                  9.30 

Butter 65.60  17.60  16.80 

The  fixed  oils  are  not  composed,  however,  of  a  single 
substance,  but  are,  for  the  most  part'  mixtures  of  at  least 
three  closely-related,  proximate  fatty  principles,  viz., 
stearin  (from  attap,  suet),  margarin  (from  ^apyapov,  a 
pearl),  and  olein  (from  &<uov,  oil).  The  two  former  are 
solid,  the  latter  liquid  at  ordinary  temperatures.  As  the 
amount  of  olein  increases,  so  does  the  softness  of  the  fat, 
while  the  boiling  point  correspondingly  falls. 

Saponification. — Fats  cannot,  it  is  well  known,  be  mixed 
with  water.  If,  however,  a  quantity  of  caustic  potash  be 
added,  an  emulsion  is  formed,  and  the  water  is  found  to 
be  united  with  the  greasy  matters.  The  reason  of  this 
alteration  in  the  properties  of  the  fat  is,  that  the  stearin, 
margarin,  and  ojein,  of  which  it  is  composed,  unite  with 
alkalies  to  form  a  transparent,  viscid  soap,  which  is  soluble 
in  water.  If  an  acid  be  added  to  the  soap  thus  formed,  it 
will  unite  with  the  alkali  and  set  free  the  fatty  matters, 
but  greatly  changed.  The  stearin,  margarin,  and  olein 
have  acquired  an  acid  reaction,  and  are  soluble  in  warm 
water ;  they  have  become  stearic,  margaric,  and  oleic 
acids.  And,  moreover,  on  removing  these  fatty  acids 
from  the  liquid,  a  peculiar  sweet  substance,  called  gly- 
cerin, remains.  The  reactions  are : — 


SOAP  AND  CANDLE  MAKING.  263 

Stearin,  C1MH110O12  +  3HO  =  Glycerin,  C6H503,3HO  + 
3  Stearic  acid,  CMHMOt,UO ; 

Margarin,  C108H104O124-3HO  =  Glycerin,  C6H503,3HO-f 
3  Margaric  acid,  CBJI3303,HO  ; 

Olein,  C1HH104012  +  3HO  =  Glycerin,  C6H503,3HO  +  3 
Oleic  acid,  C36H3303,HO. 

And,  in  case  of  palin-oil — 

Palmitin,  CI02H98O12  +  3HO= Glycerin,  C6H503,3HO-f  3 
Palmitic  acid,  C32H3IO3>HO. 

Process  Of  Soap-Making.  —  The  mixture  of  alkali  and 
fat  is  heated  together,  by  means  of  steam,  in  large  iron 
vessels,  called  coppers.  Salt  water  is  then  added  to  cut 
the  viscid  fluid  so  formed.  The  glycerin,  being  soluble  in 
brine,  is  carried  with  it  to  the  bottom  of  the  copper ;  the 
soap,  being  insoluble  in  both  brine  and  water,  rises  to  the 
surface  of  the  latter,  and  is  then  ladled  out,  pressed,  and 
cut  into  cakes. 

Process  of  Candle-Making.  —  The  object  to  be  attained 
in  the  manufacture  of  candles  is  to  get  the  fatty  acids  in 
the  free  state  and  in  a  pure  condition.  This  is  effected  in 
a  variety  of  ways :  — 

1st.  By  making,  in  the  first  place,  a  soap  out  of  fat,  by 
means  of  lime,  and  afterwards  decomposing  this  soap  with 
Sulphuric  acid.  Sulphate  of  lime,  being  insoluble,  sinks 
to  the  bottom,  and  the  fatty  acids  rise  to  the  surface  of  the 
heated  liquid. 

2nd.  By  heating  fats  with  Sulphuric  acid.  At  a  high 
temperature  the  glycerin  of  the  fat  and  Sulphuric  acid  are 
mutually  decomposed,  Sulphurous  and  Carbonic  acids  are 
evolved  and  the  fatty  acids  set  free. 

3rd.  By  injecting  steam  at  a  temperature  of  500°  and 
600°  into  heated  fat,  the  latter  is  decomposed,  and  the 
glycerin  and  fatty  acids,  in  a  separate  and  very  pure  state, 
are  distilled  over,  and  may  be  obtained  separately.  This 
is  the  admirable  process  of  Mr.  Wilson. 


264  FIXED    OILS. 

Besides  stearin,  margarin,  and  olein,  certain  fats  contain 
peculiar  proximate  fatty  principles;  thus, 

Palm-oil  yields  Palmitin,  C^H^O^; 

Butter  yields  Butyrin ; 

Beeswax  yields  Germ,  C]08HI0804,  and  Myricin,  C92H9204; 

Spermaceti  yields  Cetin,  C64H6404. 

By  saponification  of  these  fatty  principles,  we  find  that 

Palmitin,  C102H98012  =  Glycerin,  C6H503,3HO  +  3  Pal- 
mitic acid,  C32H3103,HO ; 

Butyrin  =  Glycerin,  C6H500,3HO  +  (Butyric,  Caproic, 
Caprylic,  and  Capric  acids) ; 

Cetin,  CeJI^O,  =  Oxide  of  Cetyl,  C32H35O  +  Palmitic 
acid ; 

Cerin,  C108H10804=  Oxide  of  Cerotyl,  C^O  +  Cerotic 
acid; 

Myricin,  C92H9204  =  Oxide  of  Melissyl,  C92H9204  +  Pal- 
mitic acid. 

Spermaceti  is  therefore  composed,  in  great  measure,  of 
Palmitate  of  Oxide  of  Cetyl,  C^H^O^H^Og;  beeswax 
of  Cerotate  of  Oxide  of  Cerotyl,  C54H550,C54H5303.  These 
various  compound  radicals  and  acids  are  homologues  of 
Methyl  and  Formic  acid ;  thus — 

Formic  Acid C2H03,HO 


Butyric      " 

(C2H2x3)  +C2H03,HO-C8H703,HO 

Caproic      " 

(C2H2X5)  +         "         =Ci2H1108,HO 

Caprylic    " 

(C2H2x7)  + 

'        =C16H1503,HO 

Capric        " 

(C2H2x9)  + 

«        =C20H1903,HO 

Palmitic     " 

(C2H2X15)+ 

«        =CaaH8lO,,HO 

Margaric  " 

(C2n2xi6)+ 

'        =CS4HaB08,HO 

Stearic       " 

(C2H2xl7)+ 

'        =C86H8B08,HO 

Cerotic       " 

(C2H2X26)+ 

'         -C^I^O^HO 

Melissic     '* 

(C2H2X29)+          '        =C60H5903,HO 

ESSENTIAL    OR    VOLATILE    OILS.  265 

(b)  Essential,  or  Volatile  Oils. 

The  term  essential  is  applied  to  volatile  oils,  because 
they  confer  distinguishing  smell  and  properties  to  the 
plants  composing  them. 

Preparation.  —  These  Essential  oils  are  found  in  the 
leaves,  flowers,  fruits,  and  seeds  of  plants.  In  some  cases, 
as  the  orange-tree,  the  leaves,  flowers,  and  fruit  each  yield 
a  distinct  oil.  They  are  generally  obtained  by  distilling 
the  plant  with  water,  the  plant  being  in  some  cases  fresh, 
in  others  salted  or  dried.  When  it  is  inclosed  in  cellular 
structure,  as  of  orange  or  lemon-peel,  it  is  procured  by  ex- 
pression. Though  the  boiling-points  of  these  oils  is  above 
the  boiling-point  of  water,  they  are  carried  over  with  steam 
at  212°,  and  condensed  with  it  in  a  refrigerator  attached 
to  the  still. 

Most  of  these  oils  are  lighter  than  water,  and  float  in  a 
pure  condition  upon  the  surface  of  the  water  in  the  refrig- 
erator; a  portion,  however,  of  the  oil  is  always  held  in 
solution,  constituting  what  is  termed 
perfumed  or  medicated  waters.  To  sep- 
arate the  oil  from  the  perfumed  water, 
they  are  poured  into  a  Florentine  re- 
ceiver. It  is  conical  in  form,  and  at  the 
side  is  a  spout,  b  c,  communicating  with 
the  bottom,  the  orifice  c  of  the  spout 
being  much  lower  than  the  mouth  a  of 
the  receiver.  The  distilled  product  being 
poured  into  this  vessel,  the  oil  B  separates  from  the  water 
A,  and  occupies  the  upper  part  of  the  vessel.  The  water, 
as  it  rises  above  the  bend  of  the  spout,  flows  off  at  c,  while 
the  Essential  oil  may  be  from  time  to  time  removed  by 
means  of  a  pipette. 

When  the  oil,  as  happens  with  that  from  jasmine,  violet, 
tuberose,  narcissus,  etc.,  is  too  small  in  quantity  and  too 
23 


266  ESSENTIAL    OILS. 

delicate  to  be  collected  by  expression  or  distillation,  the 
flowers  are  laid  between  woollen  cloths  saturated  with  an 
inodorous  fixed  oil.  The  latter  absorbs  the  essential  oil 
of  the  flowers,  and  afterwards,  by  digesting  the  cloths  in 
alcohol,  an  essence  is  obtained,  free  from  fixed  oil,  which 
is  insoluble  in  alcohol. 

Essential  oils  are  mostly  colorless  when  newly  made 
and  pure,  but  by  absorption  of  oxygen  they  become  yellow 
or  brown,  and  even  in  some  cases  green  and  blue.  Some 
of  them,  however,  are  bleached  on  exposure  to  light. 

They  are  generally  of  an  agreeable  odor,  strongly  aro- 
matic and  even  burning  flavor,  and  a  few  are  poisonous. 
They  dissolve  freely  in  ether  and  alcohol,  and  mix  in  all 
proportions  with  fixed  oils. 

Classification  of  Essential  Oils.— They  are  divided  ac- 
cording to  their  composition,  into 

(a)  Hydrocarbon  Oils,  composed  of  Carbon  and  Hy- 
drogen ; 

(6)  Oxyhydrocarbon  Oils,  composed  of  Carbon,  Hydro- 
gen, and  Oxygen ; 

(c)  Essential  Oils  containing  Sulphur. 

Most  of  the  essential  oils,  however,  are  mixtures  of  a 
and  b,  and  in  many  cases  the  latter,  when  isolated,  is  a 
solid,  resembling  camphor.  To  the  hydrocarbon  Berze- 
lius  gave  the  name  stearoptene,  and  totheoxyhydrocarbon, 
elaioptene  from  crtap,  fat,  or  txa«n>,  oil,  and  XT^OJ,  volatile). 
They  may  be  separated  by  cold,  which  converts  the  cam- 
phor into  a  solid,  or  by  distillation,  when  the  hydrocarbon 
passes  over  first. 

By  exposure  to  air  the  Essential  oils  suffer  two  kinds  of 
changes :  some  absorb  oxygen,  and  form  with  it  crystal- 
line and  oftentimes  acid  compounds ;  others  part  with  a 
portion  of  their  hydrogen,  which  forms  with  oxygen  water, 
and  solidify  into  resins. 

By  the  action  of  Chlorine,  Iodine,  and  Bromine,  Hy- 


OIL   OF    TURPENTINE.  267 

drochloric,  Hydriodic,  and  Hydrobromic  acids  are  formed, 
along  with  compounds  of  these  gases  and  acids,  with  the 
remaining  portion  of  the  oil.  In  violent  changes,  some- 
times thus  produced,  inflammation  occurs. 


(a)  Hydrocarbon  Essential  Oils. 

These  present  a  remarkable  sameness  of  composition, 
containing  about  88  or  89  per  cent,  of  carbon,  and  11  or 
12  per  cent,  of  hydrogen,  and  may  therefore  be  repre- 
sented by  the  formula  C5H4.  Their  different  varieties 
may  consequently  be  regarded  as  isomeric  modifications 
of  C5H4,  or  C,0H8,  or  C20H,6,  or  C4oH32.  All  these  formulae 
represent  equally  well  the  composition  of  the  oils  by 
weight,  one  being  sometimes  preferred  to  the  other 
merely  on  considerations  relative  to  their  different  vapor 
densities.  The  most  important  are  :  — 

Oil  of  Turpentine,  Camphene,  C20H16,  and  Oil  of  Lemon, 


Preparation.  —  The  former  is  obtained  by  distilling  tur- 
pentine with  water,  the  latter  by  expressing  the  yellow 
portion  of  lemon-peel.  Turpentine  is  a  viscid  fluid,  con- 
sisting of  oil  of  turpentine  holding  rosin  in  solution,  which 
exudes  at  certain  seasons  of  the  year  from  incisions  in  the 
bark  of  pine  trees.  Spirits  of  turpentine  is  impure  cam- 
phene  containing  some  rosin;  burning  fluid  is  camphene 
mixed  with  three  or  four  times  its  bulk  of  alcohol. 

By  the  action  of  Hydrochloric  acid  Camphene  and  Oil  of 
Lemons  are  each  converted  into  two  artificial  camphors, 
much  resembling  common  camphor  in  appearance  and 
properties,  one  of  them  being  solid  and  the  other  liquid  at 
ordinary  temperatures.  The  oils  of  orange-peel,  elemi, 
bergamot,  pepper,  juniper,  cubebs,  copaiba,  etc.,  are  sim- 
ilar in  composition  to  the  above,  and  are  all  isomeric,  but 
having  a  different  specific  gravity  and  boiling  point. 


268 


CAMPHORS. 


(6)  Oxyhydrocarbon  Essential  Oils. 

These  comprise  most  of  the  volatile  oils  used  for  medi- 
cine and  perfumery.  The  three  most  important,  oil  of 
bitter  almonds,  cinnamon,  and  meadow-sweet,  have  al- 
ready been  described  as  hydrides  of  the  compound  rad- 
icals benzoyl,  cinnamyl,  and  salicyl.  Of  the  remainder, 

Oil  of  Aniseed  consists  of  a  fluid  oil  and  a  crystalline 
solid,  C20H,202 ; 

Oil  of  Cumin  consists  of  Cymol,  C20H14  (liquid),  and 
Cuminol,  C20H1202  (liquid) ; 

Oil  of  Thyme  consists  of  several  substances,  chiefly 
Thymol,  C20H14O2  (solid) ; 

Oil  of  Rue  consists  of  several  substances,  chiefly  the 
liquid  CaoHsAs 

Oil  of  Cedar-wood  consists  of  Cedrene,  C32H24  (liquid), 
and  the  solid  C32H3602 ; 

Oil  of  Winter-green  consists  of  Salicylate  of  Oxide  of 
Methyl,  CuH404,HO,MeO ; 

Oil  of  Valerian,  consists  of  Valerol,  C12H1002,  Borneene 
(a  camphor),  and  Yaleric  acid. 

Properties. — It  will  be  observed  that  these  oils  are  gen- 
erally composed  of  a  fluid  portion,  which  is  a  hydrocarbon, 
and  a  solid,  containing,  in  addition  to  carbon  and  hydro- 
gen, oxygen.  The  latter,  by  oxidization,  may  sometimes 
be  changed  to  acids.  These  solid  essential  oils,  or  stea- 
roptens,  are  sometimes  included  under  the  general  head  of 

CAMPHORS, 

From  their  close  resemblance  to  the  two  crystalline  ox- 
idized essences,  originally  known  under  this  name,  viz., 

Japan  Camphor,  C20H1602,  and  Borneo  Camphor,  C20H]8O2. 

Preparation. — The  former  is  obtained  by  distilling  with 
water  the  roots  and  leaves  of  the  Laurus  camphora,  a  tree 


RESINS    AND    BALSAMS. 

found  chiefly  in  Japan  ;  the  latter  from  the  Drydbalanops 
camphor  a,  a  native  of  Borneo. 

Properties.  —  They  dissolve  sparingly  in  water,  abun- 
dantly in  alcohol  and  ether.  When  enclosed  in  a  glass 
vessel  they  vaporize,  and  are  afterwards  condensed  in 
small  crystals  upon  the  side  of  the  vessel  which  is  ex- 
posed to  the  light.  In  contact  with  Nitric  acid  the 
former  is  oxidized  to  Camphoric  'acid,  C2oH14O6,2HO ; 
the  latter  to  Japan  Camphor.  By  action  of  oxygen  on 
volatile  oils  still  another  class  of  allied  substances  is 
formed,  the 

RESINS  AND  BALSAMS. 

The  type  of  this  class  is  common  rosin,  or  colophony, 
which  is  formed  by  the  abstraction  of  1  equivalent  of  hy- 
drogen in  Oil  of  Turpentine  by  the  oxygen  of  the  air  to 
form  water;  thus,  Oil  of  Turpentine,  C20H16=C20IIi5+HO; 
and  further  oxidation  of  the  body  thus  formed,  C2oH]5,  to 
Pinic  and  Sylvic  acids,  both  of  which  have  the  formula 
C20H1502.  A  mixture  of  these  two  acids  constitutes  rosin. 

Lac,  or  Gum  Lac,  as  it  is  frequently  termed,  exudes  from 
the  punctures  made  in  the  Ficus  tree  by  insects.  It  is 
soluble  in  alcohol,  oil  of  turpentine,  and  hot  solution  of 
borax.  It  is  of  very  complex  composition,  consisting  of  no 
less  than  five  different  resins.  Largely  used  in  varnishes, 
in  hat  making,  and  forms  the  chief  part  of  sealing-wax. 
Its  most  important  varieties  are  Stick-lac,  Seed-lac,  and 
Shellac. 

Mastic,  Dammar-resin,  Sandarac,  and  Copal,  are  resin- 
ous products  from  trees  growing  in  hot  climates.  They 
are  largely  employed  in  varnishes. 

Amber  is  a  resin  which  has  exuded,  in  some  past  geo- 
logical era,  from  trees  now  extinct,  and  which  is  cast  up 
on  the  shores  of  the  Baltic  and  the  coast  of  New  Jersey 
23 


270  ESSENTIAL    OILS    CONTAINING    SULPHUR. 

in  masses  of  a  few  ounces  in  weight.  It  is  fashioned  on 
the  lathe  into  ornaments,  and  is  made  into  varnish. 

Caoutchouc,  or  Gum-elastic,  India-rubber,  and  Gutta 
Percha —  are  the  dried  juices  of  certain  tropical  plants. 
They  are  insoluble  in  water  and  alcohol ;  sparingly 
soluble  in  ether  and  the  essential  oils.  Largely  soluble 
in  chloroform.  In  oil  of  turpentine,  especially  when 
holding  sulphur  in  solution,  Caoutchouc  dissolves  to  a 
viscid,  sticky  substance.  By  heating  with  sulphur  the 
elasticity  of  Caoutchouc  is  increased,  and  it  is  rendered 
less  liable  to  be  affected  by  differences  of  temperature. 
The  new  substance  thus  formed,  and  which  is  known 
as  Vulcanized  India-rubber,  is  employed  in  the  manu- 
facture of  combs,  brushes,  knife-handles,  etc. 

The  Balsams,  such  as  Venice  Turpentine,  Canada  Bal- 
sam, etc.,  are  natural  solutions  of  resins  in  essential  oils. 
Some,  as  Peru  and  Tolu  Balsams,  and  Gum  Benzoin, 
contain  in  addition  benzoic  or  cinnamic  acid. 


(c)  Essential  Oils  Containing  Sulphur. 

The  two  most  important  of  this  class  are :  — 

Oil  of  Black  Mustard,  C8H5NS2,  and 

Oil  of  Garlic,  C6H5S. 

Preparation. — The  former  does  not  pre-exist  in  the  seed, 
but  is  formed  in  the  process  of  distillation  by  the  joint 
action  of  water  and  Myronic  acid  upon  the  pulpy  matter 
of  the  bruised  seed,  after  the  fixed  oil  which  it  contains 
has  been  expressed.  (See  Oil  of  Bitter  Almonds,  p.  246.) 

Composition. — Oil  of  Mustard  is  supposed  to  be  a  com- 
pound of  Sulphocyanogen,  C2NS2  (p.  273),  with  a  hydro- 
carbon, C6H3,  known  as  allyl,  forming  Sulphocyanide  of 
Allyl;  thus,  C8H5NS2=C6H5C2NS.. 

In  like  manner  garlic  oil  is  regarded  as  a  Sulphide  of 
Allyl,  C6H5S. 


CYANOGEN    AND    ITS    COMPOUNDS.  2fl 

VI,  CYANOGEN  AND  ITS  COMPOUNDS. 

In  consequence  of  its  close  resemblance  to  the  halogens 
this  important  radical  has  already  been  described,  p.  164. 
Like  the  halogens  it  forms  one  acid  compound  with  hy- 
drogen, and  many  compounds  with  the  metallic  elements 
which  have  the  properties  of  salts,  viz. :  — 

Hydrocyanic  or  Prussic  Acid,  HC2N  or  HCy.  (Sym.  of 
Cyanogen,  Cy.) 

Preparation.  —  Produced  by  decomposing  Cyanide  of 
Mercury  with  Sulphuretted  Hydrogen,  HgC2N  -f  HS  = 
HgS+HC2N. 

Properties. — A  thin,  colorless  liquid,  boiling  at  19°  and 
freezing  at  0°.  It  is  very  volatile,  has  a  peachy  odor,  and 
is  fearfully  poisonous.  Best  antidote  is  ammonia.  Its 
acid  properties  are  very  feeble.  Rapidly  decomposes, 
especially  when  exposed  to  light. 

Salts  of  Hydrocyanic  Acid.  —  The  Cyanides  of  Potas- 
sium and  Sodium  may  be  obtained  by  burning  Potassium 
or  Sodium  in  Cyanogen  gas.  For  commercial  use,  how- 
ever, Cyanide  of  Potassium,  KCy,  is  prepared  by  decom- 
position of  Ferrocyanide  of  Potassium  (p.  272). 

Cyanide  of  Mercury,  HgCy,  may  be  obtained  by  de- 
composing Cyanide  of  Potassium  with  Red  Oxide  of  Mer- 
cury, KCy+HgO=KO-f  HgCy.  It  is  valuable  as  a  source 
of  Cyanogen. 

The  Cyanides  of  Silver  and  Gold,  AgCy  and  AuCy3, 
are  largely  employed  in  solution  with  Cyanide  of  Potas- 
sium as  baths  for  silver  and  gold  electro-plating. 

Compounds  of  Cyanogen  with  Oxygen. 

With  oxygen  Cyanogen  forms  three  isomeric  acids :  — 
Cyanic  acid,  C2NO ; 
Fulminic  acid,  C4N2O2 ;  and 


272  FERROCYANOGEN,    ETC. 

Cyanuric  acid,  C6N303. 

The  first  is  monobasic,  the  second  bibasic,  the  third 
tribasic.  Thus  in  combination  with  silver  we  have 

Cyanate  of  Silver,  AgO,C2NO ; 

Fulminate  of  Silver,  2AgO,C,N2O2; 

Cyanurate  of  Silver,  3AgO,C6Ns03. 

Cyanic  acid,  C2NO,  may  be  combined  with  Ammonia  to 
form  a  crystalline  Cyanate  of  Ammonia,  NH40,C2NO. 
By  heating  or  by  exposure  to  air  a  little  Ammonia  is 
evolved,  and  the  crystals  are  found  to  have  undergone  a 
wonderful  change,  and  become  urea. 

The  compound  of  Fulminic  acid  with  silver,  2AgO, 
C4N202,  is  a  dangerously-explosive,  crystalline  solid. 


Compound  of  Cyanogen  with  Iron. 

Ferrocyanogen — C6N3Fe,  (Sym.  Cfy).  This  radical  has 
never  been  isolated. 

Preparation. — It  may  be  obtained  as  a  Ferrocyanide 
of  Potassium,  K2.C6N3Fe,  by  digesting  iron  filings  in  a 
solution  of  Cyanide  of  Potassium ;  Oxygen  is  absorbed, 
and  we  have  3KCy+Fe+0=KO+K2,C6N3Fe.  In  larger 
quantities  for  commercial  purposes,  this  salt  is  procured 
by  heating  the  horns,  hoofs,  hides,  or  other  parts  of  ani- 
mals with  Carbonate  of  Potassa  and  iron  filings.  It  is 
repeatedly  crystallized  from  solution  until  it  forms  large, 
transparent,  lemon-yellow  crystals,  known  in  commerce 
as  Yellow  Prussiate  of  Potash,  K2C6N3Fe-f  3HO. 

When  Ferrocyanide  of  Potassium  is  added  to  solutions 
of  metallic  salts  it  forms  oftentimes  a  beautifully  colored 
precipitate,  which  is  valuable  as  a  test.  The  Potassium 
is  simply  replaced  by  the  metal  ;  thus,  K2C6N3Fe  -f 
2(CuO,N05)=2(KO,N05)-fCu2C6N3Fe. 

Hydroferrocyanic  Acid— H2Cfy.  Like  Cyanogen,  this 
radical  also  combines  with  one  equivalent  of  Hydrogen  to 


BASIC  PRUSSIAN    BLUE — FERRICYANOGEN.          273 

form  an  acid.  But  Hydroferrocyanic  acid  is  entirely  dif- 
ferent from  its  corresponding  cyanogen  compound,  being 
very  permanent,  and  strongly  acid.  It  is  formed  by  de- 
composing Ferrocyanide  of  Copper  with  Sulphuretted  Hy- 
drogen, Cu2C6N3Fe-f2HS  =  2CuS-fH2C6N3Fe. 

Remarks.  —  It  will  be  observed,  that  in  combination 
with  the  metals  and  hydrogen,  Ferrocyanogen  is  bibasic. 

Ordinary  Prussian  Blue,  Fe4Cfy3,  is  formed  when  Ferro- 
cyanide of  Potassium  is  added  to  a  Sesquisalt  of  Iron : 
thus,  3K2Cfy+2(Fe203,3N05)=6(KO,NO5)+Fe4Cfy3.  It 
is  employed  both  in  water  colors,  and  in  oil  paintings,  as 
an  intense  blue  color,  but  it  is  not  permanent.  Dissolved 
in  water  by  means  of  Oxalic  acid,  it  forms  blue  ink. 

Basic  Prussian  Blue,  Fe4Cfy3  +  Fe A,  is  formed  by 
exposing  the  white  precipitate,  which  is  formed  when  a 
ferrocyanide  is  added  to  a  solution  of  an  iron  protosalt,  to 
the  air. 

Ferricyanogen— C12N6Fe2.    Sym.  Cfdy. 

Preparation. — A  salt  radical,  isomeric  with  Ferrocy- 
anogen, which  may  be  obtained  as  a  Ferricyanide,  by 
passing  chlorine  into  a  solution  of  Ferrocyanide  of 
Potassium. 

Properties. — It  combines  with  three  equivalents  of  Po- 
tassium to  form  Ferricyanide  of  Potassium,  or,  as  it  is 
termed  in  commerce,  Red  Prussiate  of  Potash,  K3Cfdy, 
and  with  3  equivalents  of  the  other  metals,  and  of  hydro- 
gen. It  is  therefore  tribasic. 

Remarks. — With  a  Sesquisalt  of  Iron,  Ferricyanide  of 
Potassium  produces  no  precipitate;  with  a  Protosalt,  it 
forms  TurnbuWs  Blue,  Fe3Cfdy. 

A  radical,  termed  Cobaltcyanogen,  having  cobalt  in 
place  of  iron,  and  similar  in  its  properties  and  compounds 
to  ferricyanogen,  has  been  formed. 

Sulphocyanogen— C2NS2.    Sym.  Csy. 

Preparation. — A  salt  radical,  which  may  be  obtained 


274  ORGANIC    COLORING    PRINCIPLES. 

in  combination  with  Potassium  and  Iron,  by  heating  sul- 
phur with  yellow  Prussiate  of  Potash;  K2C6N3Fe+6S= 
2(KC2NS2+FeC2]SrS2. 

Properties. — It  forms  an  acid  compound  with  hydrogen, 
Hydrosulphocyanogen,  HCsy,  and  unites  with  metals  to 
form  salts.  Those  which  are  soluble,  give  a  characteristic 
blood-red  color  with  Sesquisalts  of  Iron,  but  no  precipi- 
tate. Exists  in  the  saliva. 

Remarks. — Sulphur  may  be  replaced  by  Selenium,  and 
Selenocyanogen  and  its  compounds,  analogous  to  Sulpho- 
cyanogen  and  the  Sulphocyanides,  be  formed. 


VII.  ORGANIC  COLORING  PRINCIPLES. 

All  colors  may  be  obtained  from  organic  substances, 
but  the  prevailing  tints  are  red,  yellow,  blue,  and  green, 
or  mixtures  of  these  in  various  proportions.  They  are  all 
derived  from  vegetables,  with  the  exception  of  cochineal. 

The  Art  of  Dyeing  consists  in  applying  the  pigment  in 
such  a  way  that  it  cannot  be  washed  off.  As  a  general 
rule,  the  coloring  matter  has  not  sufficient  affinity  for 
the  fibre  of  the  fabric  to  resist  washing.  Recourse  must 
then  be  had  to  an  intermediate  body,  having  a  strong 
attraction  for  both  the  fabric  and  the  coloring  matter, 
which  may  serve  to  fasten  the  two  together.  Such  a 
body  is  termed  a  mordant,  and  the  three  principal  mor- 
dants are  Alumina,  Oxide  of  Tin,  and  Sesquioxide  of 
Iron.  When  an  infusion  of  a  dye-wood,  like  logwood,  is 
mixed,  for  example,  with  alum  and  a  little  alkali,  the  acid 
of  the  alum  combines  with  the  alkali,  and  sets  alumina 
free.  The  alumina  then  combines  with  the  coloring  mat- 
ter, forming  a  precipitate,  technically  called  a  lake,  which 
permanently  attaches  itself  to  the  fabric.  Alumina  and 


INDIGO.  275 

Oxide  of  Tin  form  bright,  Sesquioxide  of  Iron,  dull  lakes. 
When  the  mordant  is  applied  only  to  a  portion  of  the 
fabrie,  by  means  of  a  pattern,  all  the  coloring  matter  in 
the  rest  of  the  fabric  can  be  washed  out,  and  a  figure  cor- 
responding to  the  pattern  will  be  left  firmly  fastened  to 
the  stuff. 

Coloring  principles  have,  as  a  general  rule,  stronger 
affinities  for  animal  substances,  such  as  wool  and  silk, 
than  those  of  vegetable  origin,  like  cotton  and  flax.  The 
most  important  organic  coloring  matters  are : — 

Indigo. 

Litmus. 

Madder :  Alizarin  and  Purpurin. 

S  a  Slower. 

Brazil-wood  and  Logwood :  Hematoxylin. 

Quercitron;  Fustic-wood;  Saffron;  Turmeric. 

Cochineal. 

Chlorophyle. 

Indigo— C16H5N02. 

Preparation. — It  is  obtained  by  digesting  the  leaves  of 
several  species  of  the  genus  Indigofera  for  eight  or  ten 
days  in  water.  A  yellow  substance  is  formed,  which  by 
oxidation  changes  to  a  deep  blue,  and  constitutes  commer- 
cial Indigo.  By  sublimation  of  the  commercial,  pure 
Indigo,  sometimes  termed  Indigotine,  may  be  obtained. 

Properties.  —  A  tasteless,  inodorous  body,  insoluble  in 

'water,  but  slightly  soluble  in  alcohol.     It   dissolves  in 

strong  Sulphuric  acid,  and  forms  Sulphindigotic  acid  and 

Sulphindylic  acid,  C16H4NO,2S03,HO.     They  are  used  in 

dyeing  as  Saxon  blue. 

By  deoxidizing  agents,  such  as  Protosulphate  of  Iron 
and  Protocliloride  of  Tin,  the  color  of  Indigo  may  be  en- 
tirely removed,  and  white  Indigo,  C16H6N02,  be  formed. 
This  unites  with,  bases  and  forms  with  them  soluble  com- 
pounds, which  are  admirably  adapted  for  dyeing  purposes. 


276  LITMUS  —  MADDER  —  BRAZIL-WOOD,    ETC. 

By  exposure  these  solutions  become  deep  blue.  It  is  on 
this  principle  that  dyeing  with  Indigo  is  performed. 

By  boiling  powdered  Indigo  with  Hydrate  of  Potassa 
it  is  changed  to  Aniline,  C16H5N02+4(KO,HO)+2HO= 
C12H7X-f  4(KO,C02)-f  4H  (p.  24T). 

Litmus — Archil,  Turnsol  or  Cudbear.  These  blue  col- 
oring matters  are  obtained  from  the  Eocella  tinctoria  and 
other  lichens  by  exposing  them  in  a  moistened  condition 
to  the  action  of  Ammonia. 

Properties. — The  blue  color  of  litmus  is  changed  to  red 
by  acids,  and  restored  by  alkalies,  and  it  may  be  used, 
therefore,  to  detect  their  presence.  It  is  largely  employed 
as  a  red  dye.  It  is  a  compound  of  several  principles,  as 
Picro-erythrin,  C24H1604 ;  Orcein,  CUH804 ;  Rocellinin, 
C18H807 ;  and  different  acids. 

Madder — Alizarin  and  Purpurin. 

This  is  the  finest  and  most  permanent  of  red  dyes.  It 
is  obtained  from  the  root  of  the  Rubia  tinctoria,  which  is 
extensively  grown  in  southern  France,  the  Levant,  etc. 
Besides  yellow  coloring  matters,  it  yields  the  beautiful 
Madder  purple,  or  Purpurin,  C18H606+2HO,  and  Madder 
red,  or  Alizarin,  C20H606+4HO.  The  latter  is  the  chief 
coloring  principle  of  madder.  It  is  feebly  acid.  By  oxi- 
dization with  Nitric  acid  both  are  changed  to  Oxalic  and 
Phlhalic  acids,  C20H606  +  2HO  +  80  =  2(C203,HO)  -f 
C16H608. 

By  appropriate  mordants  Madder  furnishes  likewise 
brown  and  orange  colors,  and  the  exquisite  crimson 
known  as  Turkey  red. 

Safflower  affords  a  yellow  and  a  red  dye  (carthamin). 

Brazil-wood  and  Logwood.  —  The  former  yields  a  crys- 
talline solid,  termed  brezeline,  which  gives  with  mordants 
a  beautiful  red ;  the  latter,  by  digestion  in  water,  affords 
crystals  of  Hematoxylin,  C16H702.  Produces  with  iron 


ALBUMINOUS    BODIES.  277 

salts  a  permanent  black,  and  with  other  mordants  dif- 
ferent shades  of  purple  and  red. 

Red  ink  is  usually  made  by  boiling  about  two  ounces 
of  Brazil-wood  in  a  pint  of  water  for  a  quarter  of  an  hour, 
and  adding  a  little  gum  and  alum. 

Quercitron;  Fustic-wood;  Saffron;  Turmeric. — Furnish 
yellow  dyes.  The  color  of  Turmeric  is  changed  to  brown 
by  alkalies,  for  which  it  may  therefore  be  employed  as  a 
test. 

Cochineal.  —  A  brilliant  red  dye,  obtained  by  steeping 
the  dried  bodies  of  a  little  insect,  the  Coccus  cacti,  in 
water  or  alcohol.  It  is  precipitated  by  alumina  and  oxide 
of  tin,  as  carmine. 

Chlorophyle.  —  A  waxy  substance,  of  a  green  color, 
formed  in  those  parts  of  plants  which  are  exposed  to 
light,  and  communicating  to  them  their  green  tinge. 


VIII.  ALBUMINOUS  BODIES. 

The  three  most  important  are  Albumen,  Fibrin,  and 
Casein.  They  all  agree  in  yielding,  as  the  first  product 
of  their  decomposition  by  caustic  alkali,  protein  (from.pro- 
teuo,  I  am  first) ;  and  some  have  supposed  that  the  com- 
bination of  protein  with  sulphur  and  phosphorus  produced 
Albumen,  Fibrin,  and  Casein.  This  is  doubtful. 

Protein— C24H17N308. 

A  white,  inodorous  solid,  capable  of  combining  with 
both  acids  and  bases.  It  is  precipitated  from  its  acid 
compounds  by  tannic  acid  and  alkalies. 

The  chemical  formulas  of  Albumen,  Fibrin,  and  Casein 
have  not  been  determined,  but  they  contain,  as  far  as  can 
be  learned  with  regard  to  bodies  which,  like  these,  are 
amorphous,  in  100  parts:  — 
24 


278  ALBUMEN  —  FIBRIN. 

Albumen.          Fibrin.  Casein. 

Carbon  .........................  53.5                52.7  53.83 

Hydrogen  ......................     7.0                  6.9  7.15 

Nitrogen  ........................  15.5                 15.4  15.65 

Oxygen  .........................  22.0  23.5 


Sulphur  ........................     1.6  1.2  /"' 

Phosphorus  ...................     0.4  0.3 

The  above  analyses  show  that  they  closely  agree  in 
composition,  and  they  may  indeed,  under  certain  circum- 
stances, be  converted  into  each  other. 

Albumen. 

Source.  —  It  is  found  nearly  pure  in  the  white  of  eggs, 
from  which  it  derives  its  name,  in  the  serum  of  blood,  and 
in  vegetables. 

Properties.  —  It  exists  in  two  states  ;  as  a  liquid  in  the 
white  of  eggs,  the  humors  of  the  eye,  serum  of  the  blood, 
etc.,  and  as  a  solid  in  the  brain  and  nerves  of  animals,  and 
in  the  seeds  of  plants.  In  the  former  condition  it  is  color- 
less, tasteless,  inodorous,  and  soluble  in  alkaline  solutions  ; 
in  the  latter  a  translucent,  horny,  amorphous  body.  Liquid 
Albumen  is  coagulable  by  heat,  by  nitric,  sulphuric,  hydro- 
chloric and  metaphosphoric  acids,  by  metallic  salts,  by 
astringent  bodies,  like  tannic  acid  and  creosote,  and  by 
alcohol.  Owing  to  its  coagulation  by  corrosive  sublimate, 
Albumen  is  useful  as  an  antidote.  Its  coagulation  by 
acids  is  due  to  its  combination  with  them  as  a  base  ;  by 
metallic  salts,  to  its  union  with  the  oxide  of  the  metal  as 
an  acid. 

Fibrin.  —  Like  albumen  it  exists  in  two  states  ;  1st,  as 
the  chief  component  of  muscular  fibre,  whence  its  name, 
in  the  clot  of  blood,  etc.;  2nd,  as  gluten,  the  adhesive, 
pasty  mass  obtained  from  cereal  grains  after  the  starch 
has  been  removed. 

Properties.  —  When  fresh  it  forms  white,  elastic  fila- 
ments, which  are  tasteless,  inodorous,  and  insoluble,  ex- 


CASEIN  —  GELATIN  —  KREATIN.  2T9 

cept  in  alkaline  liquids.  It  coagulates  spontaneously,  and 
forms  the  clot  in  blood.  The  Fibrin  obtained  from  venous 
blood,  however,  is  not  identical  with  that  of  arterial  blood, 
and  neither  agree  in  composition  with  the  Fibrin  of  the 
flesh. 

Casein. 

Source. — Is  found  in  the  curd  of  milk  (caseum,  whence 
its  name),  in  the  blood,  and  in  peas,  beans,  and  similar 
plants — vegetable  Casein,  or  legumine. 

Properties.  —  It  is  soluble  in  alkaline  solutions.  Its 
solution  in  milk  is  due  to  the  alkali  present,  and  if  the 
latter  be  removed  by  an  acid,  like  lactic  acid,  the  Casein 
coagulates  and  forms  curd.  The  same  effect  is  produced 
by  the  dried  stomach  of  a  calf,  rennet. 

There  are  many  other  proximate  organic  principles  con- 
taining nitrogen,  such  as  Albuminose,  Pancreatin,  Mu- 
cosin,  Crystallin,  Musculin,  Ostein,  Keratin,  Synovin, 
Spermatin,  etc,  but  we  will  consider  only  Gelatin  and 
Kreatin. 

Gelatin. 

Source.  —  By  the  action  of  hot  water  on  animal  mem- 
branes, skin,  tendons,  and  bones,  they  are  made  to  dis- 
solve and  to  furnish  solutions,  which  on  cooling  deposit  a 
yielding,  tremulous  mass,  called  Gelatin.  It  is  familiar  as 
ealves'-foot  jelly,  and  in  the  dry  state  as  glue  and  isinglass, 
or  the  dried  swimming-bladder  of  the  sturgeon. 

Properties.  —  As  already  mentioned  (p.  251),  the  pro- 
cess of  tanning  depends  upon  the  formation  of  an  insoluble 
compound  of  the  Gelatin  contained  in  the  hides  with 
tannic  acids. 

The  Gelatin  obtained  from  cartilages  differs  from  the 
above,  and  is  termed  chondrin.  While  Gelatin  proper 
affords  no  precipitate  with  alum  and  acetate  of  lead,  chon- 
drin does. 

Kreatin — C8H9N304,2HO.     It  is  a  colorless  and  beauti- 


BLOOD. 

fully  crystalline  body,  which  may  be  obtained  from  the 
juices  of  the  flesh. 

Of  the  animal  fluids  we  shall  consider, 

1.  Blood, 

Description. — When  freshly  drawn  it  appears  to  be  a 
homogeneous,  red  fluid,  of  slightly  saline  taste,  peculiar 
odor,  and  somewhat  unctuous  touch.  Under  the  micro- 
scope, however,  it  is  found  to  consist  of  a  nearly  colorless 

Fig.  162.  Fig.  163.  H(lUid'  SerUm  °f  tke   bl°°d> 

or  liquor  sanguinis,  and 
multitudes  of  little  red 
discs,  the  red  corpuscles, 
and  colorless  globules, 
white  corpuscles.  Fig.  162 
shows  the  corpuscles  in  the 
blood  of  a  frog,  and  Fig.  163  as  they  appear  in  human 
blood. 

On  standing,  the  fibrin  and  corpuscles  form  a  coagulum 
or  clot,  and  leave  the  thin,  yellowish  fluid,  termed  serum, 
in  a  pure  state. 

The  analysis  of  blood  gives :  — 

Water 784. 

Red  Corpuscles 131. 

Albumen 70. 

Salts 6.03 

Fatty  substances  and  Extractive  matters 6.77 

Fibrin 2.2 

1000.00 

The  salts  found  in  the  blood  are  chloride  of  sodium  and 
potassium ;  carbonates,  phosphates,  and  sulphates  of  po- 
tassa  and  soda;  carbonates  of  lime  and  magnesia;  phos- 
phates of  lime,  magnesia,  and  iron. 

The  extractive  matters  are  kreatin,  fatty  bodies  like 
seroline,  and  cholesterin  which  is  likewise  found  in  bile, 
oleic,  margaric,  and  other  acids. 


BILE — SALIVA — GASTRIC   JUICE — MILK.  281 

A  most  delicate  test  for  blood  is  furnished  by  certain 
dark  lines  of  absorption,  seen  with  the  spectroscope,  p.  56. 
(See  London  Quarterly  Journal  of  Science,  April,  1865, 
p.  198.) 

2.  Bile.  —  It  is  a  yellow  or  green  fluid,  of  unpleasant 
smell  and  extremely  bitter  taste.     It  consists  of  various 
salts,  fats,  mucus,  and  other  substances  found  in  other 
solutions,  along  with  a  peculiar  fat,  termed  cholesterin, 
and  a  resinous  body,  bilin. 

3.  Saliva. — It  is  characterized  by  the  presence  of  a  pe- 
culiar principle,   termed  ptyaline,   in   combination   with 
sulphocyanogen. 

4.  Gastric  Juice.  —  In  addition  to  muriatic  and  lactic 
acids,  and  various  salts,  the  gastric  juice  contains  pepsin, 
to  which  its  digestive  power  is  chiefly  due. 

5.  Milk  consists  of  a  watery  fluid,  in  which  are  sus- 
pended  globules   of  butter,   surrounded  by   albuminous 
envelopes,  and  holding  in  solution  various  salts  and  milk- 
sugar.     By  churning  these  envelopes  are  broken,  and  the 
butter  collects  into  a  mass. 


24* 


APPENDIX. 


EXTENSION  has  three  dimensions,  length,  breadth,  and 
thickness.  These  may  be  considered  separately,  in  pairs, 
or  all  together. 

Extension  in  length  is  measured  and  expressed  by 
certain  arbitrary  scales  and  units,  shown  in  the  follow- 
ing tables,  where  the  relation  of  various  units  is  also 
given. 

Measure  of  Length  used  in  the  United  States, 


Miles. 

Furlongs. 

Chains. 

Rods. 

Yards. 

Feet. 

Inches. 

1. 

8. 

80. 

320 

1760. 

5280. 

63360 

.125 

1. 

10. 

40 

220. 

660. 

7920 

.0125 

.1 

1. 

4 

22. 

66. 

792 

.003125 

.025 

.25 

1 

5.5 

16.5 

198 

.00056818 

.0045454 

.045454 

181818 

1. 

3. 

3G 

.00018039 

.00151515 

.0151515 

060606 

.33333 

1. 

12 

.000015783 

.000126262 

.001262626 

.00505050 

.027777 

.083333 

1 

Length  and  breadth  multiplied,  or  taken  together,  give 
surface.  Thus,  a  rectangular  area  measuring  one  yard 
on  each  of  its  sides  we  call  a  square  yard,  and  by  the 
same  term  denote  any  area  of  equal  extent,  whatever  its 
shape. 

(283) 


284 


APPENDIX. 


-4-3 


o 

r^ 


s        " 


.2      03      M 


.22    ^ 

fe! 

m     .:     fl 


"  *°   2 

+3    _ ,     03 

&-S  8 


(M 

M 

3 

CO  GO  <N  rH 

^o 

0              S 

! 

,       1       1 

PH 

gcc^c 

1 

8  8is 

I 

«s^  •  •  • 

*3 

T 
P 

I,«I 

Barrel. 

§    ??i°2l^S 

rH         c5  O  '0  C^l  O 

S    .?jSqqq 

1 

S 

s 

siiiii 

6 

APPENDIX. 


285 


Dry  Measure, 

Liquid  Measure. 

4  gills          =       1  pint. 

4  gills 

1  pint. 

2  pints         =       1  quart. 

2  pints 

1  quart. 

8  quarts       =       1  peck. 

4  quarts         = 

1  gallon. 

4  pecks       =      1  bushel. 

16  gallons         = 

1  half  barrel. 

31£     " 

1  barrel. 

Cubic  Measure. 

42       « 

1  tierce. 

1728  cubic  inches  =  1  cub.  foot. 

63       «              = 

1  hogshead. 

27     "     feet      =1    "    yard. 
128     «       «        —  1  cord. 

84       " 

2  hogsheads   — 

1  puncheon. 
1  pipe  or  butt. 

40  feet  round,  50  feet  square, 

2  pipes           = 

1  tun. 

timber  =  1  ton. 

Table  for  Comparison  of  French  and  English  Measures  for  Length. 


Metre 

1  = 

2  — 

3  = 

4  = 

5  = 

6rr 

7  = 

8  = 

9  = 

Yards 

1.093 

2.187 

3.280 

4.374 

5.468 

6.561 

7.655 

8.749 

9.842 

Feet 

3.280 

6.561 

9.842 

13.123 

16.405 

19.685 

22.966 

26.247 

29.528 

Inches 

39.390 

78.741 

118.112 

157.483 

196.853 

236.224 

275.595 

314.966 

354.337 

Decimetre 

1  = 

2  ~ 

3  = 

4rr 

5  - 

6  = 

7  = 

8  = 

9  = 

Feet 

0.328 

0.656 

0.984 

1.312 

1.640 

1.968 

2.296 

2.624 

2.952 

Inches 

3.937 

7.874 

17.811 

15.748 

19.685 

23.622 

27.559 

31.496 

35.433 

Centimetre 

1  = 

2  = 

3  = 

4  = 

5  = 

6  = 

7  = 

8  = 

9  = 

Inches 

0.393 

0.787 

1.118 

1.574 

1.968 

2.362 

2.755 

3.149 

3.543 

Millimetre 

1  — 

2  = 

3  = 

4  = 

5  = 

6  = 

7  = 

S  = 

9rr 

Inches 

0.039 

0.078 

0.118 

0.157 

0.196 

0.236 

0.275 

0.314 

0.354 

Example  of  method  employed  with  this  Table  to   re- 
duce French  to  English  measure. 

Required  to  reduce  4612  Metres  to  Feet. 

4000  Metres  =  13123.       feet. 

600      "  =  1968.5       « 

70      "  ==  229.66     « 

2      "  =  6.56     " 


4672 


15327.72     " 


Select  from  the  table  the  number  corresponding  to  each 
digit  in  the  given  number,  assigning  the  proper  position 
to  the  decimal  point ;  then  add  all  these  quantities ;  their 


286 


APPENDIX. 


sum   will   be   the   required   equivalent  to   the   quantity 
stated. 

Table  for  Comparison  of  French  and  English  Measures  of  Surface, 


Hectare. 

Decare. 

Are. 

Sq.  Metre. 

Square  Yards. 

Square  Feet. 

1 

10 

100 

10000 

11966.4 

107698. 

1 

10 

1000 

1196.64 

10769.8 

1 

100 

119.66 

1076.98 

1 

1.19 

10.76,  etc. 

Table  for  Comparison  of  French  and  English  Measures  of  Capacity, 


Kilolitre. 

Hectolitre. 

Decalitre. 

Litre. 

Decilitre. 

Centilitre. 

Gallons  

1. 

220. 

881.2 

10. 
1. 

22. 

88.12 

100. 
10. 
1. 

2.2 
8.81 

1000. 
100. 
10. 
1. 

.22 
.881 

10000. 
1000. 
100. 
10. 
1. 
.022 
.0881 

100000. 
10000. 
1000. 
100. 
10. 

1. 

.00881 

Tints  
Cubic  Inches 

1762.4 
61074. 

176.24 
6107.4 

17.62 
610.74 

1.762 
61.074 

.1762 
6  .1074 

.01762 
.61074 

Stere  =  1  cubic  metre  =  35.31658  cubic  feet. 

Table,  showing  the  Behavior  of  Solutions  of  Metals  with  Hydrosulphuric  Acid 
and  Hydrosulphate  of  Ammonia,  employed  successively,  (Dr.  Will.)  The 
rarer  metals  are  printed  in  italic, 


Elements  precipitated  from  their  acid 
solution   by  HYDROSULPHURIC  ACID,  as 

Bodies  precipitated  by  HYDROSULPHATE  or  AMMONIA. 

sulphides. 

•••i^                  ^^                ^^^^*^-"—  ^__ 

Soluble  in  Hydro- 

^-       *             ^x. 

^-^^             ^^^^^^^ 

-    -  —  •*  ' 

~^ 

sulphate  of   Ammo- 

Insoluble   in    Hy- 

nia,    and    reprecipi- 
tated  by  Hydrochlo- 

drosulphate of  Am- 
monia. 

As  Sulphides. 

As  Oxides. 

As  Salts. 

ric  Acid. 

Anti-     \  0 

Mercury 

, 

Nickel    ) 

Alumina 

Baryta, 

monv  I          o 

is 

y  Black. 

"^     H 

Strontia, 

Arsenic) 

Silver 

3 

Cobalt    j 

Glucina 

"If 

Lime, 

[•Yellow. 

_^  o 

"o  ^ 

in    combina- 

Tin       j 

Lead 

^2 

Manga-)   Flesh- 

Chromium 

02 

tion   with 

o  -^ 

ncso    j"  color'  d. 

phosphoric, 

Gold         } 

Bismuth 

0 

Thorina 

boracic, 

M 

& 

ox.alic,  and 

Platinum  }•  § 

Copper 

3 

Iron,          Black. 

Tttria 

some  other 

3 

.s 

acids. 

Iridium    J 

Cadmium  ,Yellow 

Zinc,          White. 

Cerium 

_o  ^ 

'"s  -§ 

Magnesia 

«£,}«"•« 

Palladium'}  £ 

Ura-  \   Brown- 
nium  j  ish-black. 

Zirconia 

l& 

in    combina- 

Rhodium   [  ~&  $ 

Titanium 

1—  1 

tion   with 

23 

phosphoric, 

Osmium     J  M 

Tantalium 

acid. 

APPENDIX. 


287 


Weight.  —  Three  scales  are  in  use.  The  Troy  and 
Apothecaries'  are  commensurate,  but  the  Avoirdupois  has 
a  different  standard.* 

Measures  of  Weight  used  in  the  United  States. 

Avoirdupois, 


Tons. 

Cwts. 

Pounds. 

Ounces. 

Drachms. 

1. 

.05 
.00044642 
.00002790 
.00000174 

20. 
1. 

.0089285 
.000558 
.0000348 

2240. 
112. 
1. 
.0625 
.0016 

35840. 
1792. 
16. 
1. 
.0625 

573440 
28672 
256 
16 
1 

The  short  ton  contains  2000  Ibs. 
Troy, 


Pounds. 

Ounces. 

Dwts. 

Grains. 

Pound  Avoir. 

1. 

.083333 
.004166 
.0001736 
1.215275 

12. 
1. 

.050000 
.0020833 
14.58333 

240. 
20. 
1. 
.041666 
219.666 

5760 
480 
24 
1 
7000 

.822861 
.068571 
.0034285 
.00020571 
1. 

Troy  weight  only  is  used  in  philosophical  experiments. 

Apothecaries', 


Pound. 

Ounces. 

Drachms. 

Scruples. 

Grains. 

1. 

12. 

96. 

288. 

5760 

.08333 

1. 

8. 

24. 

480 

.0104166 

.125 

1. 

3. 

60 

.0034722 

.041666 

.3333 

1. 

20 

.00017361 

.020833 

.1666 

.05 

1 

*  The  Troy  or  Apothecaries'  pound  is  to  the  Avoirdupois  pound  as  144 
is  to  175,  but  the  ounces  are  as  480  grains  to  43  7i  grains  Troy  or  Apoth- 
ecaries'. So  also  the  Apothecaries'  drachm  =  60  and  the  Avoirdupois 
dnichm  ==  N^\  grains  Troy  or  Apothecaries'. 


APPENDIX. 


II 


O        rHCO  10        1^ 


*~ 


Jlr 


1 

• 

5 

i 

i 

s 

a    6 
S 


*       1    °       § 


APPENDIX. 


289 


Table  of  Densities,  or  Specific  Gravities. 
Solids  and  Liquids  are  compared  with  Water  at  60° 
Fahr.  as  1 ;  Gases  with  Air  at  60°  and  Barometer  at  30 
inches  as  1.     Air  is  to  water,  under  these  conditions,  as 
1  to  815. 


Alabaster 

Alcohol,  absolute 

"  95  per  cent 

"  85  per  cent 

"  and  Water,  1:1.. 

Alum 

Amber 

Antimony,  cast 

Ash 

Asphaltum 

Atmospheric  Air 

Beech 

Bismuth,  cast 

Brass,  cast 

"  wire 

Camphor 

Carbonic  Acid  Gas 

Chlorine 

Coal,  from 1.24  to 

Cobalt  and  Nickel,  cast.... 

Copper,  cast 

"  wire 

Cork 

Diamond 

Ebony  

Fir 

Flint 

Fluor  Spar 

Garnet,  Bohemian  ..3. 69  to 
Glass,  Flint,  French 

"          "       English 

"          "       Frauenhofer 

"      Bottle 

"  Plate 

25 


1.870 

.793 

.808 

.835 

.930 

1.72 

1.08 

6.71 

.84 

1.40 

1.00 

.85 

9.82 

8.40 

8.54 

.099 

1.52 

2.47 

1.30 

7.81 

8.85 

8,89 

.24 

3.50 

1.33 

.65 

2.59 

3.19 

3.80 

3.20 

3.37 

3.77 

2.60 

2.37 


Gold,  hammered 19.36 

"      pure  and  cast 19.25 

Gum  Arabic  and  Honey..     1.45 

Hen's  Egg 1.05 

Hydrogen  Gas 069 

Ice 93 

Iron,  cast 7.20 

Iron,  malleable 7.79 

Isinglass 1.11 

Ivory 1.91 

Jasper 2.70 

Jet 1.24 

Lead,  cast 11.35 

Lignum  Vitae 1.33 

Lime,  Carbonate  of 2.71 

Linseed  Oil 094 

Mahogany 1.06 

Mercury 13.59 

Muriatic  Acid 1.20 

Naphtha 84 

Nitre 2.00 

Nitric  Acid,  concentrated     1.45 

Oak,  dry,  heart 1.17 

Olive  Oil 91 

Oxygen  Gas.... 1.10 

Parian  Marble 2.34 

Phosphorus 1.77 

Platinum,  cast 19.05 

"         hammered 23.00 

"         drawn  into  wire  21. 04 

Plumbago 2.55 

Poplar 38 

Rock  Crystal 2.65 

Salt,  common 2.13 


290 


APPENDIX. 


Silver,  hammered 10.51 

"      pure  and  cast 10.47 

Steel,  hammered 7.81 

"      soft 7.80 

Sugar,  white 1.61 

Sulphate  of  Baryta 4.43 

Lime 2.32 

Soda 2.20 

Sulphur,  native 2.08 


Sulphuric  Ether 71 

Sulphuric  Acid,  concentra- 
ted   1.84 

Tallow 94 

Tin,  cast 7.30 

Water,  fresh 1.00 

Water,  Sea 1.02 

Wax,  White 97 

Zinc,  cast 7.20 


Table  of  Tenacities,  or  Breaking  Weights. 

Selected  from  Journal  of  Franklin  Institute,  Vol.  40,  p.  340. 


Power  required  to  tear  asunder  one 

Copper,  wrought 34,000 

«        cast 24,250 

"        wire 01,200 

Gold,  cast 20,000 

Iron,  cast,  Low  Moor ...  14,067 

"      Mean  of  American  31,829 

"     wire 103,000 

"     bar,  Swedish 72,000 

"     English 56,000 

"     boiler  plate 51,000 

Lead,  cast 1,800 

"       milled 3,320 

"       wire 2,580 

Platinum,  wire 2,580 

Silver,  cast 40,000 

Steel,  cast,  maximum...  142,000 

"     spring 72,500 

"     plates,  lengthwise    96,300 

"          "       crosswise.  73,700 

"     razor 150,000 

Tin,  cast 5,000 

Zinc,  cast 3,500 

"     sheet 16,000 

Brass 42,000 

"    yellow 18,000 

Bronze 17,698  to  56,788 

Gun-metal  (Cu8:Stl) 30,000 


Sq.  Inch,  in  Avoirdupois  Pounds, 

Ash 12,000  to  16,000 

Beech 11,500 

Box 20,000 

Cedar 11,400 

Chestnut,  Sweet 10,500 

Locust 20,500 

Mahogany 21,000 

"  Spanish 12,000 

Oak,  white,  American....  11,500 

"  "  English 10,000 

Pine,  white 11,800 

Poplar". 7,000 

Teak,  Java 14,000 

«  African 17,000 

Walnut 7,800 

Willow 13,000 

Brick 290  to  750 

Chalk 118 

Cement,  Portland 400 

Glass,  plate 9,400 

"  crown 6,000 

Ivory 16,000 

Rope,  Manilla 3,200 

"      hemp 6,400 

"  wire 37,000 

Mortar 52 

Sandstone...  200 


APPENDIX. 


291 


Table  for  converting  Degrees  of  Centigrade  into  Degrees  of 
Fahrenheit. 


Cent. 

Fahr. 

Cent. 

Fahr. 

Cent. 

Fahr. 

-100° 

=  —148.0° 

—54° 

=  —65.2° 

—8° 

==  +17.60 

99 

146.2 

53 

63.4 

7 

19.4 

98 

144.4 

52 

61.6 

6 

21.2 

97 

142.6 

51 

59.8 

5 

23.0 

96 

140.8 

50 

68.0 

4 

24.8 

95 

139.0 

49 

56.2 

3 

26.6 

94 

137.2 

48 

54.4 

2 

28.4 

93 

135.4 

47 

52.6 

—1 

=   30.2 

92 

133.6 

46 

50.8 

0 

32.0 

91 

131.8 

45 

49.0 

-fl 

=   33.8 

90 

130.0 

44 

47.2 

2 

35.6 

89 

128.2 

43 

45.4 

3 

37.4 

88 

126.4 

42 

43.6 

4 

39.2 

87 

124.6 

41 

41.8 

5 

41.0 

86 

122.8 

40 

40.0 

6 

42.8 

85 

121.0 

39 

38.2 

7 

44.6 

84 

119.2 

38 

36.4 

8 

46.4 

83 

117.4 

37 

34.6 

9 

48.2 

82 

115.6 

36 

32.8 

10 

50.0 

81 

113.8 

35 

31.0 

11 

51.8 

80 

112.0 

34 

29.2 

12 

53.6 

79 

110.2 

33 

27.4 

13 

55.4 

78 

108.4 

32 

25.6 

14 

57.2 

77 

106.6 

31 

23.8 

15 

59.0 

76 

104.8 

30 

22.0 

16 

60.8 

75 

103.0 

29 

20.2 

17 

62.6 

74 

101.2 

28 

18.4 

18 

64.4 

73 

99.4 

27 

16.6 

19 

66.2 

72 

97.6 

26 

14.8 

20 

68.0 

71 

95.8 

25 

13.0 

21 

69.8 

70 

94.0 

24 

11.2 

22 

71.6 

69 

92.2 

23 

9.4 

23 

73.4 

68 

90.4 

22 

7.6 

24 

75.2 

67 

88.6 

21 

5.8 

25 

77.0 

66 

86.8 

20 

4.0 

26 

78.8 

65 

85.0 

19 

2.2 

27 

80.6 

64 

83.2 

18 

=  —0.4 

28 

82.4 

63 

81.4 

17 

=  +1-4 

29 

84.2 

62 

79.6 

16 

3.2 

30 

86.0 

61 

77.8 

15 

5.0 

31 

87.8 

60 

76.0 

14 

6.8 

32 

89.6 

59 

74.2 

13 

8.6 

33 

91.4 

58 

72.4 

12 

10.4 

34 

93.2 

57 

70.6 

11 

12.2 

35 

95.0 

66 

68.8 

10 

14.0 

36 

96.8 

65 

67.0 

9 

15.8 

37 

98.6 

292 


APPENDIX. 


Conversion  of  Centigrade  into  Fahrenheit — continued. 


Cent. 

Fahr. 

Cent. 

Fahr. 

Cent. 

Fahr. 

+38° 

=  +100.4° 

+86° 

•-=  +186.8° 

+134° 

=  +273.2° 

39 

102.1 

87 

188.6 

135 

275.0 

40 

104.0 

88 

190.4 

136 

276.8 

41 

105.8 

89 

192.2 

137 

278.6 

42 

107.6 

90 

194.0 

138 

280.4 

43 

109.4 

91 

195.8 

139 

282.2 

44 

111.2 

92 

197.6 

140 

284.0 

45 

113.0 

93 

199.4 

141 

285.8 

46 

114.8 

94 

201.2 

142 

287.6 

47 

116.6 

95 

203.0 

143 

289.4 

48 

118.4 

96 

204.8 

144 

291.2 

49 

120.2 

97 

206.6 

145 

293.0 

50 

122.0 

98 

208.4 

146 

294.8 

51 

123.8 

99 

210.2 

147 

296.6 

52 

125.6 

100 

212.0 

148 

298.4 

53 

127.4 

101 

213.8 

149 

300.2 

54 

129.2 

102 

215.6 

150 

302.0 

55 

131.0 

103 

217.4 

151 

303.8 

56 

132.8 

104 

219.2 

152 

305.6 

57 

134.6 

105 

221.0 

153 

307.4 

58 

136.4 

106 

222.8 

154 

309.2 

59 

138.2 

107 

224.6 

155 

311.0 

60 

140.0 

108 

226.4 

156 

312.8 

61 

141.8 

109 

228.2 

157 

314.6 

62 

143.6 

110 

230.0 

158 

316.4 

63 

145.4 

111 

231.8 

159 

318.2 

64 

147.2 

112 

233.6 

160 

320.0 

65 

149.0 

113 

235.4 

161 

321.8 

66 

150.8 

114 

237.2 

162 

323.6 

67 

152.6 

115 

239.0 

163 

325.4 

68 

154.4 

116 

240.8 

164 

327.2 

69 

156.2 

117 

242.6 

165 

329.0 

70 

158.0 

118 

244.4 

166 

330.8 

71 

159.8 

119 

246.2 

167 

332.6 

72 

161.6 

120 

248.0 

168 

334.4 

73 

163.4 

121 

249.8 

169 

336.2 

74 

165.2 

122 

251.6 

170 

338.0 

75 

167.0 

123 

253.4 

171 

339.8 

76 

168.8 

124 

255.2 

172 

341.6 

77 

170.6 

125 

257.0 

173 

343.4 

78 

172.4 

126 

258.8 

174 

345.2 

79 

174.2 

127 

260.6 

175 

347.0 

80 

176.0 

128 

262.4 

176 

348.8 

81 

177.8 

129 

264.2 

177 

350.6 

82 

179.6 

130 

266.0 

178 

352.4 

83 

181.4 

131 

267.8 

179 

354.2 

84 

183.2 

132 

269.6 

180 

356.0 

85 

185.0 

133 

271.4 

181 

357.8 

APPENDIX. 


293 


Conversion  of  Centigrade  into  Fahrenheit.— Continued. 


Cent. 

Fahr. 

Cent. 

4-182° 

=  +359.6° 

+230° 

183 

361.4 

231 

184 

363.2 

232 

185 

365.0 

233 

186 

366.8 

234 

187 

368.6 

235 

188 

370.4 

236 

189 

372.2 

237 

190 

374.0 

238 

191 

375.8 

239 

192 

377.6 

240 

193 

379.4 

241 

194 

381.2 

242 

195 

383.0 

243 

196 

384.8 

244 

197 

386.6 

245 

198 

388.4 

246 

199 

390.2 

247 

200 

392.0 

248 

201 

393.8 

249 

202 

395.6 

250 

203 

397.4 

251 

204 

399.2 

252 

205 

401.0 

253 

206 

402.8 

254 

207 

•   404.6 

255 

208 

406.4 

256 

209 

408.2 

257 

210 

410.0 

258 

211 

411.8 

259 

212 

413.6 

260 

213 

415.4 

261 

214 

417.2 

262 

215 

419.0 

263 

216 

420.8 

264 

217 

422.6 

265 

218 

424.4 

266 

219 

426.2 

267 

220 

428.0 

268 

221 

429.8 

269 

222 

431.6 

270 

223 

433.4 

271 

224 

435.2 

272 

225 

437.0 

273 

226 

438.8 

274 

227 

440.6 

275 

228 

442.4 

276 

229 

444.2 

277 

25* 

Fahr. 

+446.0° 
447.8 
449.6 
451.4 
453.2 
455.0 
456.8 
458.6 
460.4 
462.2 
464.0 
465.8 
467.6 
469.4 
471.2 
473.0 
474.8 
476.6 
478.4 
480.2 
482.0 
483.8 
485.6 
487.4 
489.2 
491.0 
492.8 
494.6 
496.4 
498.2 
500.0 
501.8 
503.6 
505.4 
507.2 
509.0 
510.8 
512.6 
514.4 
516.2 
518.0 
519.8 
521.6 
523.4 
525.2 
527.0 
528.8 
530.6 


Cent. 

+278° 
279 
280 
281 
282 
283 
284 
285 
286 
287 
288 
289 
290 
291 
292 
293 
294 
295 
296 
297 
298 
299 
300 
301 
302 
303 
304 
305 
306 
307 
308 
309 
310 
311 
312 
313 
314 
315 
316 
317 
318 
319 
320 
321 
322 
323 
324 
325 


Fahr. 

+532.4° 
534.2 
536.0 
537.8 
539.6 
541.4 
543.2 
545.0 
546.8 
548.6 
550.4 
552.2 
554.0 
555.8 
557.6 
559.4 
561.2 
563.0 
564.8 
566.6 
568.4 
570.2 
572.0 
573.8 
575.6 
577.4 
579.2 
581.0 
582.8 
584.6 
586.4 
588.2 
590.0 
591.8 
593.6 
595.4 
597.2 
599.0 
600.8 
602.6 
604.4 
606.2 
608.0 
609.8 
611.6 
613.4 
615.2 
617.0 


294 


APPENDIX. 


Conversion  of  Centigrade 

into  Fahrenheit.—  Co 

ncluded. 

Cent.       Fahr. 

Cent. 

Fahr. 

Cent. 

Fahr. 

4-326°  =  4-618.8° 

4-334°  : 

=  4-633.2° 

+342° 

=  +647.6° 

327       620.6 

335 

635.0 

343 

649.4 

328       622.4 

336 

636.8 

344 

651.2 

329       624.2 

337 

338.6 

345 

653.0 

330       626.0 

338 

640.4 

346 

654.8 

331       627.8 

339 

642.2 

347 

656.6 

332       629.6 

340 

644.0 

348 

658.4 

333       631.4 

341 

645.8 

349 

660.2 

Referred  to  on  page  51. 

To  prepare  a  double-image  prism  of  Iceland  spar,  we 
take  a  natural  crystal  of  that  substance,  and  using  the 
natural  face,  B  Y,  Fig.  40 ;  for  one  surface  cut  a  pointed 
wedge  from  it  so  that  the  apex  of  said  wedge  shall  be  in 
the  obtuse  angle,  Y,  and  the  new  face  make  with  the 
natural  one  an  angle  of  8°  to  10°.  We  then  prepare  a 
small  prism  of  glass,  having  a  little  less  angle,  to  correct 
the  color  dispersion  of  the  spar  prism,  and  cement  these 
together  with  Canada  balsam  as  usual. 

Iceland  spar  may  be  cut  first  with  a  fine  saw,  then 
trimmed  down  with  a  file,  "2nd  cut,  bastard,"  then  ground 
with  the  greatest  care  with  emery  of  increasing  fineness, 
and,  lastly,  polished  with  a  little  crocus  or  rouge  on  lea- 
ther. The  best  specimens  of  this  work  which  I  have 
ever  seen,  among  hundreds  by  French  and  English 
makers,  are  prepared  by  J.  Zentmeyer,  Optician,  of  Phil- 
adelphia, who,  I  believe,  is  also  the  first  successfully  to 
work  that  difficult  material  in  this  country. 

H.  M. 


LAWS  OF  CHEMICAL  COMBINATION. 


Referred  to  on  page"  25. 

LAW  I. 

The  same  substance  is  always  composed  of  the  same 
elements  in  the  same  propositions.  Thus,  water,  whether 
found  in  the  blood  of  animals,  the  sap  of  plants,  in  mine- 
rals or  chemical  salts,  in  springs,  rivers,  the  ocean  or 
the  clouds,  consists  always  of  Oxygen  and  Hydrogen 
combined,  in  the  proportion  of  8  parts  by  weight  of  the 
first  to  one  of  the  second. 

LAW  E. 

Each  element  has  a  certain  proportion  or  number  of 
parts  by  weight,  in  which  it  combines  with  others.  This 
proportion  is  called  its  EQUIVALENT,  or  ATOMIC  WEIGHT 
(being  supposed  to  represent  the  relative  weight  of  its 
final  particle  or  atom).  In  these  equivalent  propor- 
tions (or  in  simple  multiples  of  the  same),  elements  will 
combine  together,  and  in  no  other  ratio.  Thus,  the 
equivalent  of  Nitrogen  is  14,  and  that  of  Oxygen  is  8 ; 
if,  then,  we  bring  together  the  bodies  in  this  propor- 
tion they  will  combine,  leaving  no  residue ;  but  if  we 
have  9  parts  of  Oxygen,  then  one  part  of  this  would 

(295) 


296  APPENDIX. 

be  left  out,  and  would  not  enter  into  combination  with 
the  Nitrogen.  We  may,  however,  have  a  double  equiva- 
lent of  Oxygen,  i.e.  16  parts,  combining  with  the  14  of 
Nitrogen  ;  or  a  triple,  24  parts,  or  a  quadruple,  etc.  Each 
of  these  compounds  would  then,  however,  be  quite  a  dif- 
ferent substance  from  the  others. 

LAW  m, 

The  equivalent  of  a  compound  is  equal  to  the  sum  of 
the  equivalents  of  its  constituents.  Thus,  the  equivalent 
of  water  made  of  Oxygen  8,  and  Hydrogen  1,  is  9. 
That  of  Nitric  Acid,  made  of  Nitrogen  14,  and  5  times 
that  of  Oxygen  (8),  or  40,  is  54  (N05 .  Eq.  54.) 

LAW  IV. 

Like  classes  of  bodies  combine,  with  each  other  — 
Element  with  element,  Binary  with  binary,  Ternary  with 
ternary.  Thus,  Zinc  can  combine  with  Oxygen,  or  some 
other  element,  but  not  with  Sulphuric  Acid  (S03),  or 
other  binary  compound ;  but  Oxide  of  Zinc  (ZnO),  itself 
a  binary,  can  combine  with  the  binary  Sulphuric  Acid. 

LAW  V, 

(a)  When  elements  unite,  the  electro-positive  by  pre- 
ference combine  with  the  electro-negative.  (6)  When 
binaries  unite,  the  electro-negative  element  in  each  must 
be  the  same,  (c)  When  ternaries  unite,  the  electro-neg- 
ative binary  must  be  the  same,  i.e.  they  must  have  the 
same  acid. 

Examples.  —  (a)  Iron,  which  is  positive,  will  unite 
more  readily  with  Sulphur  or  Carbon,  which  are  nega- 
tive, than  with  Hydrogen,  which  is  positive.  (6)  Again, 
in  Oxide  of  Iron  (FeO)  the  Oxygen  is  the  negative  ele- 


APPENDIX.  297 

ment;  so  also  it  is  in/Sulphuric  Acid  (SO3) ;  these  may 
then  combine  ;  not  so,  however,  Oxide  of  Iron  and  Hy- 
drocloric  Acid  (HC1),  where  Oxygen  is  the  negative 
element  in  one,  and  Chlorine  in  the  other,  (c)  Lastly. 
Sulphate  of  Potash  (KO,S03)  may  unite  with  Sulphate 
of  Copper  (CuO,SO3),  having  the  same  acid,  but  not  with 
Nitrate  of  Copper  (CuO,N05),  which  has  Nitric  Acid  for 
its  negative  binary. 

It  is  found  with  regard  to  gases,  that  not  only  is  their 
combining  weight  fixed,  as  we  have  already  shown,  but 
that  they  have  a  like  relative  combining  volume.  Thus, 
Oxygen  and  Hydrogen  unite  in  the  proportion  of  one 
volume  of  the  first  to  two  of  the  second.  Hydrogen  and 
Chlorine  in  equal  volumes,  and  so  with  others.  Various 
attempts  have  been  made  to  carry  out  this  observation 
to  solid  and  liquid  bodies  by  finding  or  assuming  their 
vapor  volumes,  and  many  elaborate  deductions  have  been 
made  from  these  data;  but  the  subject  is  far  too  compli- 
cated to  be  discussed  in  such  a  work  as  the  present. 


INDEX. 


Absorption  bands PAGE  56 

Acetal 238 

Acetate  of  Allumina 239 

"             Copper 239 

"            Lead 239 

Acetic,  Acid 238 

Acetone 239 

Acid,  Acetic 238 

Benzoic 246 

Bi-nitro-benzoic  246 

Boracic 165 

Butyric 235,264 

Camphoric 269 

Capric 264 

Caproic 264 

Caprylic 264 

Carbolic 234 

Carbonic 160,  161 

Chloracetic 239 

Chloric 154 

Chromic 211 

Cinnamic 247 

Citric 249 

Cyanic 271 

Cyanuric 272 

Ferric 206 

Formic 234,241 

Fulminic 271 

Gallic 251 

Hydrated  Nitric  147 

Hydrochloric 154 

Hydrocyanic 271 

Hydroferrocyanic 272 

Hydrofluoric 157 

Hydrosulphuric 178 


Acid,  Hypochloric 154 

Hypochlorous 154 

Hyponitric 147 

Hyposulphurous 172 

Lactic 235 

Malic 249 

Margaric 262,  263 

Meconic 252 

Melissic 264 

Metagallic.. 251 

Metastannic 223 

Nitric „„.  147 

Nitro-benzoic 147 

Nitrous 246 

Oleic 262,  263 

Oxalic 248,  276 

Palmitic 263 

Perchloric 154 

Permanganic 204 

Phosphoric 187,  188 

Phthalic 276 

Pinic 269 

Prussic 271 

Pyroacetic 239 

Pyrogallic 251 

Pyroligneous 238 

Salt 180 

Silicic 166 

Stannic 223 

Stearic 262,  263 

Sulphindigotic 275 

Sulphindylic 275 

Sulphinic 170-172 

Sulphurous 169 

Syloic 269 

Tartaric 248 

(299) 


300 


INDEX. 


Acid,  Titanic 222 

Acids 128,  129 

«     Vegetable 229,248 

Acrnlein 261 

Action  of  Oxygen  and  Water 

on  Metals 178 

Adhesion 13 

Affinity,  Chemical 123 

"        Laws  of 295 

Air,  Atmospheric 144 

"     Dissolved  in  Water 142 

Albumen 277,  278 

Albuminose 279 

Albuminous  Bodies 278 

Alcohol,  Amylic 236 

Benzoic 246 

Butylic 236 

Cinnamylic 247 

Methylic 236 

Propylic 236 

Wine 236 

Alcohols 236 

Aldehyde 238 

Alizarin 276 

Alkali,  Dulcified 183 

Alkalies,  Organic 251 

"         Vegetable 183 

Alkaloids 251 

Artificial 255 

Alkarsin 244 

Alloys,  Fusible 214,218 

"       Type  Metals 223 

Allyl 270 

"    Sulphide  of 270 

"    Sulphocyanide  of. 270 

Alumina,  Salts  of. 201 

"         Silicates  of 199 

Aluminum 198 

"         Sesquioxide  of....   198 

Amalgam,  Ammoniacal 190 

Amalgamation 104 

Amber 269 

Ammonia 149 

"        Carbonate  of. 191 

"        Cyanate  of 272 

"        Muriate  of. 190 

Ammouiacal  Amalgam 190 

"  Salts 191 

Ammonias 255 

Amyl 257 

"         Ethyl 255 


Ammonias,  Methyl 257 

"            Phenyl 258 

Ammonium 190 

"          Chloride  of. 190 

"         Oxide  of. 190 

"          Tetrethyl,      Hy- 

drated  Oxide..  256 

Amyl 245 

Amylaceous  and  Saccharine 

Bodies 229 

Analyzer 64 

Aniline 234,  247,  276 

Animal  Electricity 121 

Aniseed  Oil 268 

Antimoniuretted  Hydrogen..  224 

Antimony 223 

Ant-ozone  and  Ozone...   136,137 

Archil,  Turnsol  or  Cudbear.  276 

Argentiferous  Galena 225 

Armature 91 

Arsenic 220 

'      Acid 221 

<       Bisulphide  of 221 

'       Marsh's  Test  for 221 

'      or  Ratsbane 221 

'      Reinsch's  Test  for...  222 

Arsenical  Sulphide  of  Iron..  220 

Art  of  Dyeing 274 

Artificial  Alkaloids  contain- 
ing  several   Compound 

Radicals 259 

Artificial  Alkaloids    Homo- 
logous with  Aniline 258 

Atmospheric  Air 144 

Atom 292 

Atomic  Weight 295 

Attraction,  Capillary 13 

B. 

Balsam,  Canada 270 

"       Peru 270 

"       Tolu 270 

Balsams  and  Resins 269 

Barium 192 

"      Chloride  of 192 

Barometer  Double 89 

Baryta 192 

"      Nitrate  of 192 

"      Sulphate  of 192 

Bases .' 129,  130 

"    Artificial  Organic 255 


INDEX. 


301 


Bases,  Vegetable 229 

Batteries,    Electro  -  Motive, 

Forces  of 101 

Batteries,  Thermo-Electric..  130 

Battery,  Bunsen 99 

Daniel's 98 

Electropoion 100 

Gas 102 

Gas  and  Secondary 

Piles 109 

Grove 99 

Iron  or  Maynooth..  100 

Sraee's 97 

Beeswax 264 

Benzoic  Acid 246 

"        Alcohol 246 

Benzol 334-247 

"      Nitro 247 

Benzoyl 246 

Bergamot,  Oil  of 267 

Bessemer's  Process 207 

Biborate  of  Soda 189 

Bichromate  of  Potassa 212 

Biethylamine 256 

Bile 281 

Bilin 281 

Binaries 127 

Binoxide  of  Hydrogen 143 

Bismuth 217 

Bisulphide  of  Carbon 165 

"  Iron 206 

Bitter  Almonds 268 

Bleaching  Powder  or  Chlo- 
ride of  Lime 194 

Blood 280 

"     Analysis  of  the 280 

"     Serum  of  the 280 

Blowpipe,  Oxyhydrogen 140 

Blue  Ink 273 

"    Prussian 273 

"    Saxon 275 

"    Turnbull's 273 

«    Vitriol 215 

Bodies,  Albuminous 279 

"       Diamagnetie 92 

"       Found  in  Water 142 

*c       Magnetic 92 

Boracic  Acid 165 

Borax 189 

"      Biborate  of  Soda 189 

Borneene 268 

26 


Boron 165 

Brazil-Wood 267,  277 

Breaking  Weights,  Table  of  290 

Brezeline 276 

Brittleness  of  Metals 177 

Bromine 155 

Brucia 254 

Bunsen     Battery,    Modified 

Forms  of 100 

Bunsen  and  Kirchoff,   Ana- 
lysis of  the  Sun 57 

Burning  Fluid 267 

Butyl 245 

Butyric  Acid 235,  264 

Butyrin 264 

C. 

Cadet's  Fuming  Liquid 244 

Cadmium 214 

"        Sulphide  of 214 

"        Iodide  of 214 

Caesium 202 

Caffeine  or  Theine 255 

Calcium 193 

"      Chloride  of 194 

Calomel 225 

Calorimeter,  Hare's 96 

Camphene 267 

Camphoric  Acid 269 

Camphors 268 

"        Borneo, 268 

"        Japan 268 

Canary  Glass,  Fluorescence 

of: 58 

Candle  Making,  Process  of...  263 

"       Wilson's  Pro- 
cess    263 

Cannon,  Electrical 86 

Caoutchouc 270 

Capillary  Attraction 13 

Capric  Acid 264 

Caproic  and  Caprylic  Acid..  264 

Caramel 234 

Carbolic  Acid  or  Phenol 234 

Carbon 158 

"      Amorphous 159 

"      Bisulphide  of. 165 

"     Metalic 159 

"      and  Nitrogen,   Com- 
pound of 164 


302 


INDEX. 


Carbon  and  Sulphur,  Cora- 
pound  of 165 

Carbonic  Acid 160,161 

"         Liquid 161 

Acid,  Solid 162 

Oxide 160 

Carburetted  Hydrogen 238 

Carry's  Apparatus 31 

Casein 277-279 

Cast  Iron 206 

Cedar-Wood  Oil 268 

Cedrene... 268 

Cells 95 

Centigrade  into  Fahrenheit 

291,  292,  293 

Cerin 264 

Cerium 201 

Cerotyl,  Oxide  of 264 

Cetin 264 

Cetyl,  Oxide  of. 264 

Charcoal 159 

"        Animal 159 

Chemical  Affinity 123,  124 

"        Combination,  Laws 

of 295-297 

"        Physics 9 

Chemistry 123 

"         Inorganic 125 

"         Organic 228 

Chime  of  Bells,  Electric 77 

Chloracetic  Acid 239 

Chloral 240 

Chloric  Acid 154 

Chloride  of  Nitrogen 155 

Chlorine 151,  152 

Bleaching 153 

"       and  Oxygen 154 

Test  for 153 

Chlorophyle 277 

Chlorous  Acid 154 

Cholesterin 280 

Chondrin 279 

Chromate  of  Lead 212 

Chromatic    Aberration,    its 

Correction  61 

Chromic  Acid 211 

Chromium 211 

Cinchona 253 

Cinchonia 252 

Cinchonicine 253 

Cinchonidine..., 253 


Cinnamic  Acid 247 

Cinnamon,  Oil  of 247 

Cinnamyl 247 

Cinnamylic  Alcohol 247 

Circularly  Polarized  Light..     71 

Citric  Acid 249 

Classification  of  Metals 179 

Coal-Tar 233 

"        Oil 233 

Cobalt 209 

"      Chloride  of 210 

Cobaltcyanogen 273 

Cochineal 277 

Cohesion 13 

Coil,  Medical  Induction 117 

Coil,  Ruhmkorff 117 

Coils    and   Solenoids,    Mag- 
netic Properties  of Ill 

Coke 159 

Collodion  232 

Colophony  or  Rosin 269 

Coloring  Principles,  Organic  274 

Columbium 224 

Compass,  Tangent 113 

Complementary  Colors 54 

Condensation 32 

Condenser  of  Fizeau 118 

Conducting  Power  of  Solids, 

Table  of 34 

Conducting  Power  of  Gases     34 
"  '«      of    Sub- 

stances for  Electricity..     74 
Conduction  of  Electricity...     83 

Heat 33 

Conductors  and  Insulators..     74 

Conia 255 

Contraction,  Application  of.     23 

Convection,  Electricity 83 

Heat 35 

Copaiba,  Oil 267 

Copal 269 

Copper 214,  215 

"      Black  Oxide  of 215 

"      Pyrites 214,  215 

"      Sulphate  of 215 

Corpuscles,  Red 280 

White 280 

Corrosive  Sublimate 225 

Couples,  Galvanic 95 

Creosote , 233 

Criopherous 31 


INDEX. 


303 


Crystallin ...  279 

Crystallography 16 

Culinary  —  Paradox 28 

Curd 279 

Current,  Primary 115 

"         Secondary 115 

Currents 119 

"         Moving    in    Wires, 

Properties  of 110 

Cyanic  Acid 271 

Cyanide  of  Gold 271 

"  Mercury 271 

"  Silver 271 

Cyanogen 164,  230 

"          and  its  Compounds 

271-274 

"          with    Iron,    Com- 
pounds of 272 

"          with  Oxygen, Com- 
pounds of 271 

Cyanol 234 

Cyanuric  Acid 272 

D. 

Dammar-Resin 269 

Daniel's  Hygrometer 146 

Density 11 

"      of  Gases 12 

"      of  Liquids 11 

"      of  Solids 11 

Dew  Point 146 

Dextrine ' 232 

Diamond 158 

Didymium 201 

Discharge , 84 

"         Disruptive 84 

"         Flame 84 

"         Glow 87 

Discharger,  Universal 85 

Diffraction 40 

Diffusion    of    Liquids    and 

Gases 14 

Dispersive  Powers 60 

"              "      Table  of...  60 

Distillation 33 

Distribution  of  Electricity...  80 

Double  Fluid  Theory 72 

Double-image  Prism 51,  294 

Double  Refraction 50 

"             "          in  Glass...  51 


Double    Refraction   in    Ice- 
land Spar 50 

Double  Refraction  in  Quartz     51 

Drummond  Light 194 

Dyeing,  Art  of. 274 

Dyalysis 14 

E. 

Earths,  Metals  of  the  Alka- 
line   192 

Effects  of  Heat 21 

Elaioptene 266 

Electric  Egg 59 

"       Lamp,  Duboscq's...  106 
Electrical  Attraction  and  Re- 
pulsion    76 

Electrical  Machine 75 

"         Relation  of  Sub- 
stances, Table  of  73 

"         Umbrella 73 

Electricity 71 

"         Animal 121 

"         Induction  of. 81 

"         Statical 72 

Electrodes  or  Poles 96 

Electrolysis 108 

Electro-Magnet 92 

"        Gilding 109 

"       Plating 109 

Electrometer,  Coulomb's 79 

Electrophorus 81 

Electroscope,  Gold-leaf 79 

Electrotyping 109 

Elements 125 

"         Electro  -  chemical, 

Order  of. 95 

"         Nomenclature  of...  126 

"         Symbols  of 127 

Table  of 126 

Elemi  Oil 267 

Elliptically  Polarized  Light.  71 

Erbium 201 

Essences 266 

Essential  Oils,  Hydrocarbon.  267 
"           "    Oxyhydrocar- 

bon 268 

"          "         containing 

Sulphur 270 

"       or  Volatile  Oils 265 

"        or    Volatile    Oils, 

Classification  of.  266 


304 


INDEX. 


Etching     by     Hydrofluoric 

Fusible  Metal  218 

Acid 

157 

Fusion                                           23 

Ether    Hydrobromic            .  . 

242 

Fustic  Wood  277 

Hydrochloric  

242 

242 

242 

G. 

Sulphuric  •  

238 

Gallic  Acid  251 

Ethyl  

229 

Galvanic  Batteries  96 

255 

Compounds    .               • 

243 

ment  of  102  104 

Methyl  

242 

"         Current    Chemical 

Ethylamine  

255 

Effects  of  107 

32 

Galvanic  Currents,  Effects  of  105 

Exciting  Liquids 

95 

"               "         Velocity 

Expansion 

21 

in  Good  Conductors  111 

Applications  of 

23 

"         Induction....              114 

in  Freezing  

26 

Galvanism  94 

22 

Gnlvanometer                            113 

of  Liquids 

22 

Gas,  Illuminating    .     .            233 

of  Solids      

22 

Gases,  Conducting  Power  of    34 

Extension  

283 

"        Density  of  12 

Extra-Currents  

119 

"        Diffusion  of  14 

"        Transpiration  of  14 
Gassiot's  Cascade  58 

F. 

Gastric  Juice  281 

Fats 

261 

Gelatin  .        .        .                      979 

Fermentation 

235 

General  Properties  of  Matter       9 

Ferric  Acid 

206 

Ghost  42 

Ferricyanide  of  Potassium 

273 

Glass  200 

273 

"    Soap  for                            221 

272 

"    Stained  .                              G9 

Fevrocyanogen 

272 

Glucinum  201 

Ferrous  Salts  

209 

Glucose  232 

Fibrin                                 277 

278 

Glycerin                                     '?G2 

Fireed  Oil 

261 

Gold    226 

Fizeau's  Condenser 

118 

"    Mosaic  223 

Flfimeless  Lamp  

227 

Graphite  or  Plumbago  158 

267 

Gravitation                                   10 

Fluorescence 

58 

Gravity  .                     10 

Fluorine 

156 

"       Specific  10 

Ply  Powder.       

221 

Green,  Scheele's  221 

Formation    of    Images    by 

"         Schwunfurt  221 

48 

"        Vitriol  208 

Formic  Acid 

241 

Gum  231 

221 

"    Arabic                                231 

54 

'    Benzoin  .          .                 270 

Freezing   Congellation 

25 

'    Elastic  270 

"         Mixtures 

24 

<    Lac  269 

«               «        T'ible  of 

25 

'    Senegal                              231 

Fulminic  Acid  

271 

'    Tragacanth  231 

Fusel-Oils... 

241 

Gun-cotton  or  Pyroxyline...  232 

INDEX. 


305 


Gunpowder 185 

Gutta-Percha 270 

Gypsum 195 

H. 

Haloid  Salts 242 

Hardness  of  Metals 177 

Heat 16 

"    Animal 18 

"    Effects  of 21 

"    Measurement  of 18 

"    Sources  of. 17 

Hematoxylin 276 

Hydrated  Nitric  Acid 147 

"        Oxide    of    Tetre- 

thylammonium  256 

Hydro-Carbons 162 

"  "         Neutral 234 

Hydrochloric  Acid 154,  155 

Hydro-Electric  Machine 76 

Hydroferrocyanic  Acid 272 

Hydrofluoric  Acid 157 

Hydrogen  Antimoniuretted.  224 

"          Bicarburetted 162 

"          Binoxide  of. 140 

"          Organ 140 

"  with  Oxygen, 

Compounds  of.   141 
"          Protocarburetted  162 

"          Sulphuretted 217 

Hydrometer 12 

Hydrosulphocyanogen 274 

Hydrosulphuric  Acid 173 

Hygrometer,  Daniel's 146 

"  Regnault's 144 

Hypochloric  Acid 154 

Hypochlorous  Acid 154 

Hyponitric  Acid 147 

Hyposulphurous  Acid 172 

I. 

Iceland  Spar 195 

India-Rubber 270 

"  "  Vulcanized 270 

Indigo 275 

"  White 275 

Indigof erra 275 

Indigotine 275 

Indium 202 

26* 


Induction  of  Electricity 81 

"         Galvanic 114 

Ink,  Black 212,  251 

"     Blue 273 

«     Red..., 277 

Inorganic  Chemistry 125 

Interference  39 

Iodine 156 

Iridium 228 

Iron 205 

«    Cast 206 

"    Compounds  of 206-208 

Isomeric  Bodies 253 

J. 

Juice,  Gastric 281 

Juniper  Oil 267 

K. 

Kakodyl 244 

"        Oxide  of 244 

Keratin 279 

Kreatin 279,  280 

L. 

Lac,  or  Gum  Lac 269 

"     Seed 269 

"     Stick 269 

Lactic  Acid 235 

Lake 274 

Lampblack 159 

Lanthanum 201 

Latent  Heat 24 

"          "     of  Gases 29 

"           "     of  Liquids....  23,  24 
Laws  of  Chemical  Combina- 
tion   295-297 

Lead  and  Compounds...  215-217 

"      Red 217 

Lemon  Oil 267 

Leucoline 234 

Leyden  Jar 32 

Light 37 

Circularly  Polarized...     71 

Drummond 194 

Elliptically  Polarized.     71 

Lime 140 

Propagation  of 38 

Properties     of     Plane 
Polarized 64 


306 


INDEX. 


Light,  Sources  of 37 

"       Velocity  of 38 

Lightning  Rods 80 

Lignine  of  Wood,  etc 231 

Lime  and  Compounds...   193-195 

"    Light 140 

.^-Liquefaction 32 

'      Liquids,  Diffusion  of. 14 

Latent  Heat  of 28 

Lithium 189 

Litmus,  Archil,  Turnsol,   or 

Cudbear 276 

Loadstone 90 

Logwood 276,  277 


M. 

Madder 276 

"       Purple 276 

"       Red 276 

Magnesia     and      Com- 
pounds ...  197,  198 

"         Citrate  of. 250 

"         Phosphate  of  Am- 
monia and 197 

Magnesium    and    Com- 
pounds... 196,  197 

«          Wire 196 

Magnet 113 

"       Artificial 90 

"       Dr.  Jayne's 93 

Magnetic  Properties  of  Coils 

or  Solenoids Ill 

Magnetism 89 

"  by  Induction 94 

Magnetizing  Effects 110 

Magneto-electric  Machine...   116 

Magnets,  Horseshoe 91 

Malic 249 

Manganese    and    Com- 
pounds   202,  203 

Margaric  Acid 262,  263 

Margarin 262,  263 

Mass 10 

Mastic 269 

Matter,  Extension,  Bulk,  or 

Volume 9 

"       Figure 10 

"       General    Properties 

of 9 

"       Impenetrability  of...     10 


Matter  Indestructible 10 

Meconic  Acid 252 

Medical  Induction  Coil 117 

Medicated  Waters 265 

Measurement  of  Heat... 18 

Measures  of  Capacity,  French 

and  English 286 

"        of  Capacity  in  the 

United  States  ...  284 

"        Cubic 285 

Dry 285 

"        French    and    Eng- 
lish   285,  286 

for  Length.... 285 

Liquid 285 

"        of  Surface 284 

"        of  Weight   in   the 

United  States 287 

"        of  Weight,  French 

and  English 288 

Mechanical  Forces 10 

Melissic  Acid 264 

Melissyl,  Oxide  of. 264 

Mercaptan 240 

Mercury 224 

"        Cyanide  of 271 

"        Bromide  of. 225 

Iodide  of 225 

"        Subchloride  of 225 

Metal 278 

Metals 177 

"      Chemical    Properties 

of 178 

"      Classification  of 179 

"      Color  of 177 

"      Ductility  and  Mallea- 
bility   178 

"      Fusible 218 

"      Hardness,Brittleness, 

and  Tenacity 177 

"      Malleability  and  Duc- 
tility    178 

"      of  the  Alkaline  Earths  192 

"      Smell  and  Taste 177 

"      Specific  Gravity  of  ...   178 

Metaphosphate  of  Soda 188 

Metagallic  Acid 251 

Metastannic  Acid 223 

Methyl 229 

"      Compounds  of 224 

"      Ethers...,  ..  224 


INDEX. 


30f 


Methylic  Alcohol 240 

Milk 281 

Mispickel 220 

Mixture    of    Nitrogen    with 

Oxygen 144 

Molasses 234 

Molybdenum 219 

Mordant 274 

Morphia 252 

Mosaic  Gold 223 

Mucilage 231 

Muriate  of  Ammonia 90 

Muscovin 279 

N. 

Naphthalin 234 

Needle,  Astatic  92 

"        Magnetic 92 

Neutral  Bodies 130 

Newton's  Rings..  44 

Nichols'  Prism 63 

Nicotina 255 

Nitric  Acid 147 

"      Oxide 146 

Nitrogen 143,  144 

"       Chloride  of. 155 

"       and  Hydrogen,  Com- 
pounds of 149 

Nitrous  Acid 147 

Oxide 146 

Nomenclature  of  Elements..  126 

0. 

Oil  of  Aniseed 268 

Bergamot 267 

Bitter  Almonds 268 

Cedar-wood 269 

Cinnamon 247,  268 

Coal-tar 233 

Copaiba 267 

Cubebs 267 

Cumin 267 

Elemi 267 

Fusel.... 241 

Garlic 270 

Juniper 267 

Lemon 267 

Mustard 270 

Orange-peel 267 


Oil  of  Pepper 267 

Rue 268 

'       Thyme 268 

'       Turpentine 267 

'       Valerian 268 

'       Wintergreen 268 

Oils 229,  260 

"    Classification  of. 260 

"    Vegetable  and  Animal..  260 
"    Essential,  containing  Sul- 
phur   270 

"  "  or  Volatile...  230 

"    Fixed 261 

Olein 262,  263 

Oleic  Acid 262,  263 

Orange-peel  Oil 267 

Orcein 276 

Organ,  Hydrogen 240 

Organic  Alkalies  or  Alkaloids  251 
"         Table  of....  252 

Bases 241 

"     or    Alkaloids, 

Artificial 255 

Coloring  Princi- 
ples..  230,  274 
"             "            Matters, 
the  most  impor- 
tant   275 

Osmium 228 

Ostein 279 

Oxalic  Acid 248,  276 

Oxide,  Carbonic 160 

of  Cerotyl 264 

'  Cetyl 264 

<  Kakodyl 244 

Melissyl 264 

<  Nitric 146 

1       Nitrous 146 

Oxyhydrogen  Blowpipe 140 

Oxygen 131 

"       Preparation  of..  131-135 

"       Properties  of 135 

Ozone  and  Ant-ozone...  136,  137 

P. 

Paraffine 233 

Paranaphthalin 234 

Palladium 227 

Palmitin 263 

Palmitic  Acid 263 


308 


INDEX. 


Pancreatin 279 

Pearlash 183 

Peat 232 

Pepper,  Oil  of 267 

Pepsin 281 

Perchloric  Acid 154 

Permanganic  Acid 204 

Peruvian  Bark 253 

Pheyol 234 

Phosphorescence 59 

Phosphoric  Acid 187,  188 

Phosphorus 174,  175 

"          and  Iodine 177 

"          Oxide  of....  175,  176 
Phosphuretted  Hydrogen  Gas  176 

Phthalic  Acid 276 

Picoline 234 

Picro-erytherin 276 

Pile,  Dry 101 

Piles,    Secondary,    and    Gas 

Battery 109 

Pinic  Acid 269 

Pitch 233 

Pitch-balls,  Dancing 78 

Plane  Polarized  Light 62 

"  "  "     Color- 

ed Effects  of    76 

Plaster  of  Paris 195 

Platinum 226 

"       Sponge 227 

"       Wire 227 

Plumbago  or  Graphite 158 

Polarity 16 

Polarized  Light 62 

Polarizer 64 

Poles  or  Electrodes 96 

Potash,  Chlorate  of 185 

"       Red  Prussiate  of....  273 

"       Yellow  Prussiate  of..  272 

Potassa  and  Compounds  183,  184 

Potassium 181 

"         Ferricyanide  of...  273 
"         Ferrocyanide  of..  272 

Powders,  Seidlitz 187 

Properties  of  Currents,  mov- 
ing freely  in  Wires 110 

Properties  of  Plane  Polar- 
ized Light 64 

Propyl 245 

Protem 277 

Protochloride....  ..  212 


Protosulphide  of  Iron 206 

Protoxide  of  Iron 205 

Primary  Current 115 

Prism,  Double-image 51,  284 

"      Hollow 53 

"      Nichols' 63 

Prussian  Blue 273 

11  "    Basic 273 

"  "    Ordinary 273 

Prussic  Acid 271 

Purpurin 276 

Pyroacetic  Acid 239 

Pyrogallic  Acid 251 

Pyroligneous  Acid 238 

Pyrophosphate  of  Soda 188 

Q. 

Quercitron 277 

Quinia 253 

"      Muriate  of 253 

"      Sulphate  of. 253 

Quinidine 253 

Quinoidine 253 

R. 

Radiant  Heat 36 

Radiation 36 

Rainbows,  Artificial 52 

Red  Lead 217 

"    Prussiate  of  Potash 273 

"    Turkey 276 

Reflection 41 

Refraction 45 

Regnault's  Hygrometer 144 

Rennet 279 

Repulsion 15 

Resin,  Dammar 269 

Resins  266 

"      and  Balsams 269 

Revolving     Arch,     Thermo- 
electric   121 

Rhodium 228 

Rocellium 276 

Rochelle  Salt 249 

Rock  Candy 234 

Rosin 267 

"      or  Colophony 269 

Rotation    of    the    Polarized 

Ray 69 


INDEX. 


309 


Rubidium 202 

Rue  Oil  268 

Ruhmkorff  Coil 117 

Ruthenium  228 


S. 


Saccharimeter 

Sacharine    and   Amylaceous 

Bodies 229, 

Saffron 

Salgeratus 

Sal  Ammoniac 

Salicin  

Salicyl 

Salicylate 

Saliva 

Salt,  Basic 

Glauber 

Rochelle 

Tribasic 

of  Tartar 

Salts 

Acid: 

Ammoniacal  

Bibasic 

Double 

Ferrous 

Monobasic 

Neutral, 

Sandarac 

Saponification 

Saxon  Blue 

Sealing-wax 

Secondary  Current 

Seidlitz  Powders 

Selenium 

Selenocyanogen 

Seroline .. 

Sesquioxide  of  Iron 

Shellac  

Silicic  Acid 

Silicon 

"      Compound  with  Oxy- 
gen  

Silvor  and  Compounds...    ... 

"      Cyanate  of 

"      Cyanide  of 

"      Cyanurate  of 

"      Fulminate  of 

Soap-making,  Process  of. 


70 


230 
277 
183 
190 
247 
247 
268 
281 
180 
187 
187 
180 
249 
179 
180 
191 
180 
180 
209 
180 
180 
269 
262 
275 
269 
115 
187 
174 
274 
280 
205 
269 
166 
166 

167 
225 
272 

271 
272 
272 
263 


Soda  and  Compounds  ...  186-188 

Sodium 186 

"  Chloride  of 186 

Solenoid 113 

Solenoids  or  Coils,  Magnetic 

Properties  of Ill 

Specific  Heat 20 

"  "  of  Gases  and 

Vapors  Compared  with 

Water 21 

Specific  Heat  of  Solids  and 

Liquids,  Table  of 21 

Spectroscope 56 

Spectrum 53,  54 

"  Analysis 55 

Spermaceti 264 

Spermatin 279 

Spherical  Aberration 49 

Spheroidal  State 34 

Stannate  of  Soda 223 

Stannic  Acid 223 

Starch 230 

Statical  Electricity 72 

Stearic  Acid 262,263 

Stearin 262,  263 

Stearoptene 266 

Strontium 193 

Strychnia 254 

Sublimation 33 

Sugar 234 

"  Barley 234 

"  Cane 234 

"  Grape 234 

Sulphindigotic  Acid 275 

Sulphindylic  Acid , 275 

Sulphocyanogen 273 

Sulphur 168 

Sulphuric  Acid 170-172 

Sulphurous  Acid 169 

Sun,  Analysis  of 57 

Supercarbonate  of  Soda 187 

Symbols  of  Elements 127 

Syloic  Acid 269 

Synovin 279 

T. 

Table  of  Breaking  Weights..  290 
"      of  Centigrade  Degrees 

into  Fahrenheit,  291-293 
"      of  Conducting  Power 

of  Solids...,  ,     34 


310 


INDEX. 


Table  of  Dispersive  Powers     60 
««      of     Electrical     Rela- 
tions of  Substances,     73 
«     of      Electro-chemical 

Order  of  Elements,      95 

«      of  Elements 126 

"      of  Fahrenheit  Degrees 

into  Centigrade,  291-294 
"     of  Indices  of  Refrac- 
tion   45,46 

"     of  Measures 284-286 

"     of  Organic  Alkalies  or 

Alkaloids 252 

"      of  Reflecting  Powers,     43 

"     of  the  Specific  Heat  of 

Gases   and    Vapors 

Compared          with 

Equal     Weight      of 

Water 21 

of  the  Specific  Heat  of 
Solids  and  Liquids,      20 

"      of  Tenacity  290 

"     of  Weights 287 

Tangent  Compass 113 

Tantalum... 224 

Tartar  Emetic 224,  249 

Tartar,  Salt  of 183 

Tartaric  Acid 248 

Telegraph,  Morse's 110 

Tellurium 220 

Tenacity  of  Metals 177 

«       Table  of,  290 

Terbium 201 

Ternaries 130 

Thalium 202 

Theine 255 

Theory  of  the  Double  Fluid,     72 
Thermo-electric     Revolving 

Arch 121 

«       Electricity 120 

"       Multiplier 121 

Thermometers 18 

"  Centigrade...      19 

"  Fahrenheit...     19 

"  Mercurial 19 

Spirit 19 

Thorium 201 

Thyme  Oil 258 

Tin 222 

"  Compounds  of 222,223 

"  Cry  of 222 


Tin  Stone 222 

Titanic  Acid 223 

Titanium,  Compounds 222 

Toluol 234 

Transfer  of  Electricity 83 

Heat 33 

Transpiration  of  Gases 14 

Triethylamine 256 

Tube  Aurora 87,  88 

Tubes,  Geissler 87,  88 

Turkey  Red 276 

Turpentine 267 

Oil 267 

"          Spirits  of 267 

"          Venice 270 

Turmeric 277 

Turnsol  or  Cudbear  and  Ar- 
chil   276 

Tungsten 219 

Type  Metal 223 

U. 

Undulations  of  Light,  Length 

of 55 

Uranium 218 

V. 

Vacuum,  Absolute 89 

Valeral 268 

Valerian  Oil 268 

Vanadium 219 

Vaporization 26 

Vegetable  Acids 248 

Velocity  of  Galvanic  Cur- 
rents for  Good  Con- 
ductors   Ill 

Venice  Turpentine 270 

Veratria 254 

Vermilion 225 

Vinous  or  Alcoholic 235 

Viscous 235 

Vitriol,  Green,  White.........  213 

W. 

Water,  Air  dissolved  in 142 

"      Other   bodies    found 

in...  ..   142 


Hard. 


187 


INDEX. 


311 


Water,  Spring  and  Well 143 

Waters,  Medicated 265 

"       Perfumed,.,. 265 

Wax,  Sealing 269 

Weight 10,  287 

Apothecaries' 287 

Avoirdupois 287 

Comparative   Tables 

of 288 

Troy 287 

White  Vitriol 213 

Wintergreen  Oil 268 

Wood,  Brazil 276 

Ether 236 

Fustic 277 

Log 276 

Naphtha 240 

Spirit 236 


X. 
Xyloidin 232 

Y. 

Yellow,  King's 221 

"  Prussiate  of  Potash.  272 
"  Turner's 217 

Yttrium ..  201 


Z. 

Zinc 212 

"  Red  Oxide  of 212 

"  Silicate  of 212 

"  Sulphate  of 213 

"  White 213 

Zirconium 201 


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